There is probably some out of the box way to go about this. So I am going to see if we can't all make something new that can help fund OOO's and their great game, in a way that doesn't change the spirit or game play for anyone else. This Thread, at least the OP will get cleaned up and your ideas, legitimate criticisms and calls for solutions, alterations or questioning for someone to alter, and observations of glaring problems will be implemented and you WILL get credit!

A cheaper monthly sub price, with less advantages would probably work a lot better than any other (also much less thought out) ideas I have seen, possibly with at most 3 tiers up to the $10 range for a few extra features that aren't game breaking, but just nice, along the spirit of CE purchasing but tailored specifically, especially for the more hardcore, time invested, or other specific crowd.

SORRY FOR THE LENGTH! But Please at least the read the parts that are numbered which contain the ideas and the jist of benefits. The math part is pretty much the rest.
QUICK TL;DR PRICE BREAK DOWN
Including a $2.50 p/month option could be doable too, for just recurring Upgrades, and a small benefit for recurring payments.
Model 2: Prices are listed meaning in range.
$5 p/month All upgrades and 1 other Major benefit
$7.50 p/month All upgrades, Better Luck w/ 2 Minor benefits (or 1 Upgraded Minor Benefit)
$10 p/month All upgrades, BL, w/ 4 Minor benefits, with any 2 combined for one UG Minor

Model 1: Same price ranges, but everything breaks down, with only Half Upgrades w/ other big benefits (Explained Below) and then 2 minor benefits per $2.50 increase, that can be used on the same benefit to make it better, like getting All Upgrades instead of Half.

Basically, either model at 10$ you could get 4 or 5 extra benefits, 2 per extra $2.50 or so with 5$ being the minimum. We will use $5 as an assumption, considering it "in that range" with increments of $2-$4 depending, since the upgrades have a set CE value at 800 a month and the benefits could be balanced in different ways, and the "Subscription/Money Tiers" could include increasing benefits that are exponential, as guaranteed money is a huge supplement for any company, and even better than random purchases when the Sub time is bought in advance (I mean in a long term, stability sense.)

The amount of Sub time bought at once, extras for using a recurring payment, or whatever else OOO's would do is on them, but I suggest a minimum of around $5 for the biggest perks and maybe 1 extra for subscribing, $5 for the main draws, as it keeps CE and gives you a bonus benefit.This would increase by two for whichever "Money Tier" (I'll refer to them as this henceforth) you are paying per month, whether recurring or through buying pre-paid months or year/s.

They could let people either buy time ahead of time or recurring monthly, and possibly even add an extra perk (Let's call them perks henceforth too) with large-time purchases, or let people choose to pay full and get extra benefits or get a deal and get the normal amount. Also, just ideas.

Now, the meat of the equation: I have compiled tons of rough and open ended ideas, with as many possibilities for each that I could, just to get the idea across and to show that their are MANY things that could work and not destroy many aspects of game play, or even hardly change, while some would even create cheaper CR spending for F2Pers and others may create or support CR and CE sinks! I don't doubt that some perks that I will suggest, if hypothetically implemented, only could if they weren't possible to combine with X perk because of certain reasons, compounding benefits etc.

My second model I think would work is having Upgrades as the main draw to Subscribing, with the choice of 1 other "High Tier Perk." This allows them to choose Better Luck, in whatever form OOO"s makes it, or a CE weekly allowance that give's you 225-250CE at the end of each week, which gives you an extra 100-200CE per month for the normal buy prices for 800CE (while getting 900-1kCE.) The CR increase could be made a major perk, but I will address that momentarily. After picking the 2 Major Perks, for every extra "Money Tier" they go up, they get 2 extra "normal" perks, with other possible benefits like the jump from an extra 100 to 200 CE for their allowance per month (so up to 1kCE) or an added important luck increase, up to the 10 dollar max, with 4 normal perks for that price with possible main or major perk's improving. The minimum could also be $2.50 a month for All upgrades and a minor perk.

The first model I didn't expand on would break everything down, with Half the upgrades or full upgrades being your first two options, then Better luck and an extra minor perk at the $5 range, then the rest of the perks be broken down into either separate minor perks worth half of $2.50 per month, or have two settings so you can still pay $7.50 range for upgrading to a full 900-1kCE weekly/per/month allowance, or taking half that and a 1 Token boost every Token gain w/ increase in Token drops. All the perks aside from, although it's not impossible to do so, Better Luck would have 2 "strengths" that would be choose able, and you can mix and match 2 for every "Money-Tier." Little more complex yet more choices than the other model, and small benefits could be included for the guaranteed income, like extra CE through purchases, etc. The possibilities are endless!

Though, I think it would be best to balance them all in a way that they could be used and chosen with any combination, which is why each has many possibilities and extra, sometimes pushing it. They are there as ideas, which can be changed and molded.

EXAMPLES (As in just food for thought! They are somewhat in order of probable compatibility and utility, from balanced at high levels then descending from lop sided to less of both basically.)

1: All upgrades! Trinket/weapon slots included monthly (Something that would probably be the best feature to include, in one form or another, ie. Just weapon slots or just trinket slots, with all as one of the extra benefits for +2.50$ addition to your current choice for Sub cost and package, or just include as the main included cost, and have the other benefits be your "extra" for guaranteeing OOO's 10$ each month, or whatever Sub package/deal you purchase. So pay 5$ and you get all upgrades monthly, which is 800CE normally or $2.50, but then 2 benefits, and "Extra Luck" with the other benefits choosable at per extra $$7.50 up to 10$)

2: Better Luck! with however many aspects of the game they could include, from everything to only the most important or compatible yet useful things, including, but NOT mandatory to include, OR limited to; A better chance for 4* and 5* Mat drops, or ever lower rarity mats; bigger minerals; Lock-boxes and Prize Wheel benefits/drops that could even include having a better chance to benefit the Knight's current situation (like low health, or just lack of X vial type, maybe even tailored to the current gate map or next Depth) though only Lock-boxes may be the most compatible; UV's on all gear in general more or less, though possibly also increasing the chance of useful ones, or strength, or decreasing the chance of a useless one (Jelly Damage on a Piercing Weapon, etc.) or whatever OOO's data would determine would work best, which would more likely be just more UV's (with a very small increase in chance of a higher strength?) during crafting, and higher strength or better complimenting UV's to the item when paid for at the Bazaar (Probably just strength as better complimentary UV's would have to have such a slight increase in their chances that it wouldn't be worth it, otherwise not being compatible enough to implement if made any higher); a slightly higher chance for rare monsters; better chance for extra tokens (If not made a separate choice) during boss fights, drops from boxes/monsters, or PvP, or even all three depending on the increase and the Butterfly affects, and I'm sure their are many more that could be included.

Better Luck could be made with any combination of these or anything other that I missed, at any actual increase, and be a neat addition/benefit/perk to get for paying a recurring Sub fee for the Upgrades and other benefits. the biggest one being even a TINY increase in UV's from the select players that would pay for this would have in my opinion a positive effect in the economy, as those who craft to sell, or ragecraft to sell won't stop regardless and therefore it won't have a huge impact on the economy besides making some UV's a bit cheaper, which limits profits to those who CR sinks are made for, and those who ragecraft fr their own gear will be more inclined to get a Sub, still need CE, and have tons of other gear to make things on the AH cheaper, which when you combine all of these basically reinforces the time and CE sink of ragecrafting, which even if done for not as long by the ragecrafter since the chances are higher, is offset by the Sub cost, and the rest of us enjoy the binders extras and the sellers goods that he can make faster, more often, and therefore more accessible to us! Everyone wins!

Basically, since it costs you the Sub money to get the perk to OOO's, and only so many people would pay the recurring fees or even pick this perk (unless it was one of the auto ones), and honestly would probably create a CR sink for the rest of us, P2P or not, in the sense as it would be much easier to try out different gear, UV's or not considering the extras with no/crap/decent UV's that would be increasingly cheap since there is more ragecrafting since they are making more money, while the best still get's sold for tons, just a little less tons, so the sellers still make a buck while also having more gear themselves to try out for cheaper. My economic sense is decent, and I doubt this would have any real affect on the CR price of CE besides making it at least temporarily go down ( Meaning the combination of Sub benefits in all) and although OOO's doesn't like this, as it means people will buy less directly, it will make more lower-end Sub paying players and also be offset by the income from Sub prices!

Back to the other ideas...

3: Elevator costs are refunded or reduced when completed, but still cost full if you leave back to Haven. Again, could work as an option depending on OOO's data. Even a small refund (10E per Depth abandoned, 5-8E per Completed) would even be worth it over time.
3 1/2: Cheaper energy rev costs, possibly included in 3 or on it's own with 1-6 extra hearts split between you and any player you revive or revives you. Simply another energy saver for a monthly fee, which could also be included at the right rate standard with the upgrades, with a choice to make them even cheaper.

4: Extra tokens during boss fights and PvP, and even boxes or possibly monster drops! Adding a guaranteed extra token in every boss fight, along with a set increase in chance for the 3 other tokens to drop, and a guaranteed Krogmo Coin per PvP match would be a neat perk. It could be easily changed or altered to balance out, as possibly an extra 1 every X amount of runs or maybe it would take 2 per run... again; OOO's data needed.

5: Mist regeneration increased by X amount (Determined through testing variables etc. that again OOO's would only be able to determine. Although, would probably be most compatible as an automatic Sub feature at a low increase (1.5-3X), with maybe another extra increase (4-5X)
5 1/2: Weekly allowance of CE (Probably around 100-300CE, maybe a bit less possibly more, and depending on OOO's data, and price, AGAIN of course) as one of the benefit choices through extra (More than 5$) monthly payment, but also could be varied weekly depending on X variable for any price; time played (either more or less per hour, OOO's decision again), CE bought in past 30 days (so basically choosing this benefit would add a weekly CE boost depending on how much you have bought in 30 days, with a cap and possibly a minimum), Depths completed/LD or BN matches done, Bosses killed, based off of CR's at time of allowance payout (more or less CR could give you more CE, OOO's data needed :P) or many other factors.

Also, a CE allowance choice is a way for OOO's to sell cheaper energy, but that only comes on predetermined days, once a week after a Sub payment for a month, especially if it's varied on game play, or even if it's set, like $2.50 get's 2 Perks under our first model, which means we get one thing about equal to this allowance in weekly benefit and we get 250CE a week. That's 200CE extra for getting it in increments supplementing our purchased/CR bought CE. Now, this still encourages spontaneous buys, especially of larger amounts, and even more-so for crafting and let alone ragecrafting. It is just a nice perk. It may be one of the better ones, which may work better the second "Perk-Tiers" model, but either way, it's a possibility that could benefit OOO's with the Sub cost, guaranteed revenue and pre-paid Subs, and also help us. It may work better at an extra 100CE a month, who knows besides OOO's.

6: Any mist not used can be refunded for half, or more probably much less, like 15-20 per 100 depending on what OOO can determine through their data to be the most compatible in CE. Automatic setup may be the only way to make it work, with your account out of use and only refunding the ME while you aren't logged on, and resetting timer-wise if you do. (Iffy one here, which depends a ALOT on OOO's data which I don't, though wish, have. Although, even only getting around 3CE per 100ME not used every 24 hours, or less if using extra ME regeneration, would be useful if the ME isn't destroyed or at least full when logging on again. This is most true when people take breaks or if they only play every couple or few days, or even more so only during weekends and such. It's just a thought, but it could also have a menu for people who choose it to set up when and how unused ME is converted at a higher turnout, or just creating a much smaller (like the 3CE) amount every 12/24 hours, and when it should stop conversion so they have it when they know they will or can play again, unless gaining CE interest. It's something that could probably be implemented in some form in F2P and not hurt the game, but make people feel better when they are low on CE for Elevator's cost or have a RL and can't play, so they feel they are still earning something.) This idea could have serious ramifications and isn't probably worth doing, at least not for a while, in any real useful form.

7: Crown drop increased. Obviously this would increase need for some CR sink, which I know we will have more of. Though, if the Better Luck perk was implemented for Sub P2Ps this would offset it a bit, and the increase in CR drops could include Mat drops also, but be equivalent so OOO's is still gaining and the player benefiting, and it still being equal to other benefits payouts in ways to get CE. (This probably should be higher up, as it's easily balanced and many players who like earning CE through playing or grinding CR would get a small boost here and not have to pay much a month to make the game better and support it, while still not easily gaining CE through cash and not really experiencing their love of the development cycle!)

Alright, these again are all just rough, random and yet still expanded ideas. I didn't worry about thinking every little bit through but more so just getting down as much as I could think of, as it may spark ideas in one of YOU! Tell me what you think, as I think these are some ideas, that if they are chopped up and then rebuilt wouldn't mess up anyone's game play and could even be introduced slowly (Only $5 Subs, or the $2.50 tier too) and in an infinite amount of ways and possibilities.

I just think something like this, implemented slowly, could really help fund the game. A lot of the ideas are kind of P2W faster, but that's what we already have!!! And this actually slows that down quite a bit in theory, with allowances and better crafting etc.

Anyway, sorry for the length! Please let me know what you think and I will include it in the main post which will get cleaned up, and you will get credit for your contributions!

And, GL and have fun!!!

PS: This post may be a bit incoherent at spots as I won't have time to clean it up til morning, but I hope to see some ideas being bounced around and retorts/input for the OP itself, which should eventually be the subscription option that would give us the benefits we want, without changing the spirit of the game itself or it's style and play, and without breaking the economy and actually helping the game and all of us have more fun and create our own play styles. And of course, what WE would pay for it. :)