Regarding Prize Box Only Content (and why players should want it)

I play a game called Puzzle and Dragons and it gets content updates regularly, seven years after release, with a large player base, and enough money made to fund artists, voice actors, quality of life updates, all of that.
It does this by selling the content that people want for money.
But this isn't fair, you are probably thinking. The mixmaster was a disaster, because it locks F2Pers out of the game and no one gets to experience content and... Well GungHo, the Puzzle and Dragons developers, have a good solution to this, too.
They give out a taste of the new content regularly. A big taste.
First you get a lot of resources over time. Imagine if we got free energy every day. Not mist energy, just flat out say, 200 free energy that can stack over time. Then imagine if we could buy prize boxes off the depot for 1,000 energy each. That's their model. Every 5 days you earn a free chance to get a new monster- the equivalent of a new weapon in Spiral Knights. Not all weapons are created equally. You have about a large chance at getting something mediocre and a relatively small chance at getting one of the better units. We too love gambling so I don't see a problem.
Second, there are a LOT of bundles and one time deals. Would you buy 20K ce for 10 dollars? 100K + some rarities for 65 dollars? Well their sales spiked drastically when they came out with these deals recently. There are also exciting monthly deals to promote the game. If you logged into P&D last November you got 100 free stones, which was the same as getting about 50K ce. And yet. Well. It worked. Sales spiked, and all the F2Pers got a ton of nice stuff. Free stuff being given out = more sales. Fascinating.
Thirdilly, they don't just put everything behind the semi-permeable paywall. They put out new levels and farmable stuff too! And the farmable stuff is hard to get, but fair. If I want something I can use my resources to get it within one event, and there is some RNG but the rates are relatively kind. Typically, there are a couple good monsters that drop and are needed in large quantities to complete a new unit, and after a few days of grinding I am able to attain and max out the thing.
Fourthully they do eventually give out the old harder to get units at easier rates. Everything is brought back. There is no unspoken rule that everything that comes out is only there once and you will never see it again, because you almost certainly will see it again. Not only that, but units that were once the big token item are often given away as prizes in massive quantities. Imagine if you got a prize for earning dauntless delver on every arcade gate that comes out.
So if you want content, get them to sell it to you and then buy it off of them.
The common opinion is that content must be separate from prize boxes and not paywalled at all, as some kind of freebie. This doesn't give the developers any kind of incentive to create it, and creates a culture where all they create are costume items.
We need to change our opinion of the developers and be more understanding to their plight.
The developers need to find a way to sell content, so that they don't have to work other jobs and can create content.
Please discuss and consider this.

+1 to this
Also the biggest problem of this game economy it's overloaded with sellers and there's not enough buyers unless it's low end stuff that you can sell on AH.
It absolutely kills my motivation to play the game as I'm not much of a grinder person 2 runs and i already want to die out of boredom so l mostly use SK as a social / dress up platform.
Having ways to obtain such costumizables would definitely make me more interested in doing those said achievements to reach the prize.
This is from a end gamer perspective as I've done everything that SK has there to do.

Hello, hiss.
Old veteran knight here, just chiming in to mention that the Ward Shield skin got me to log in again, hiss.
As long as the cosmetics don't provide a heavy in game advantage, I am quite fine with spending a little money for CE or Prize Boxes. And if it helps generate more content/tilesets, that's fine too, hiss.

I like these discussions of alternative funding/content models.

What if: (Let me use owlite wand as an example)
1.) We can get a 3* version of the wand for free, however it would have a 30-day expiration. It would be mailed to all players after the owlite box was added on SD.
2.) We can upgrade it to 4* but a recipe would be needed, the recipe can be obtained as a uncommon loot from owlite boxes (10-15% chance). The wand would become a permanent equipment after upgrading to 4*.
- The 3* wand cannot be used to complete the hall of heroes mission for 3* certification.
- To not ruin the 5* version, 3* and 4* wand will have a lower attackspeed(medium) than it's 5* variant.
- We cannot upgrade a 4* wand to 5*, similar to BK Mask and BKC
- Ofc the 3* and 4* wand's skin would look like prototype versions of the 5* wand, just like OCH weapons and Seerus Mask, it's name is different too.
Dry Owlite Branch
- 3 star
- It's skin would be a short wooden dry branch with stems + a small glow on it's tip.
Refined Owlite Branch
- 4 star
- It's skin would be similar to it's 3* version, except that it's slightly longer and looks polished. The glow on it's tip is also brighter.

@Bopp
Mmm yes thank you but do actually add to the discussion. They gave you a purple spiral because you're unable to think for yourself but I've seen your sword guide and know that you're capable, deep down, of independent thought, just as mecha knights, retrodes, and the technology behind Facebook are capable of that sort of thinking. I believe in you, buddy!
@Tpen
No, you're still stuck in the mindset of things being made fair and available and balenced because then you can save the game from whatever or feel better about yourself. And I'm sorry to disappoint you, but these growing the game things take time and probably aren't going to happen and you're never going to feel good about yourself, and even if I do somehow convince you of anything here someone else will take your place here or on another forum. I could go on.
The point however, is that we need a very serious paradigm shift away from this philosophy of paid weapons being evil and unfair and into a more accepting state, where we see new content as new content regardless of whether it comes from a prize box at a 2% rate or not.
The flip side is that paid weapons do not satisfy or grow the game or really accomplish anything. They make a quick buck, and then everyone that considers joining the game sees how expensive it is, how paying money feels awful, and well, they don't want to play the old Spiral Knights.
If we can move beyond these views and into some kind of a system that works for everyone, and I do believe the game mentioned in the OP has accomplished this, then we can perhaps achieve something.
Now get mad and give me that delicious retort or go cry because you know deep down that I'm right. Ugh. I hate everything.

The way you lay out the OP screams mobile game. While I don't necessarily disagree with the concepts, Spiral Knights had several mobile game functions early on that it has since shed as they didn't help the game and in fact inhibited it (ie, mist elevators).
I think that having a mini mist tank (energy that players can spend for small things in the clockworks, such as mecha knights or danger rooms that recharges very slowly and can increase in max size depending on your prestige) would be a nice way to implement "free" energy. The idea of giveaways would be nice, but I think that arcade gate clears or prestige mission clears should grant prize boxes, especially surprise boxes.
Personally, I think that surprise boxes would be the best way to get F2P players premium content. If a surprise box contains every promotional box ever, and then updates as we get new boxes, that would be a fantastic way to keep the new promo items new and fresh because with a huge pool of potential rewards, players are very unlikely to get a box they want from a surprise box, but they can get some cool outdated items that they will enjoy.
In mobile games, crafting gear to max level is limited by your rank, and usually you just overwhelm the player with a bunch of bad things so they get rid of them in favor of the few good things. Spiral Knights doesn't give you ten beast bashers and a silent nightblade for you to upgrade, and I don't think such a model would work too well for SK's actual game design, not just profit design.
The special energy bundles is a really good point. I assure you anyone who's spent money on the game has spend money on the special packs (starter + battle), plus whenever the guardians armor pack is on sale it's a huge deal. Having more "buy energy now and get bonus energy for a limited time" sounds like a great idea - you can even loop it into gameplay making all things that involve energy being less expensive so all players benefit - ie, supply depot prices drop 10%-20%, danger rooms and and mecha knights only take 1 energy to open/activate, and bribing king krogmo only takes 10 energy instead of 25.
That's my two cents on it. I think the mobile model on its own won't work, but certain elements could be extracted and work very well in the SK realm of things.

That is largely what I was getting at, Fangel. I don't expect Spiral Knights to mimic phone games perfectly and function like they do, but I would love for them to learn and move on from the current model. There's no sense Stalin when you can be moving towards that utopia...
And. While the main idea of this is to put more unique and interesting weapons into the game as paid content and to allow the F2P a means of attaining those independently of competing with other players (i.e. featured auction), the other big takeaway would be more interaction with the community. You know what happens every time GungHo streams? They get flamed by their community. Yet everyone loves them deep down because they release challenge dungeons and new mechanics and most of all new units for people to buy. That's just how it works.
People dont mind paying extravagant sums for very rare items
but then at the same time it is a good idea to let everyone else have some fun in RNG as well, without expending real life money