I have recently come back to Spiral Knights, and while I still absolutely love the game (Even got into a really sweet clan, which would increase the longevity of my enjoyment.) I'm afraid to pay more money for it. The game feels like it's at the end of it's lifecycle, and this is the second time, I'm told, the Apocrea is making an appearance.
Here's a few suggestions to make things more interesting...
Monster changes:
Gremlin Mender: I'd like to see them regain the ability to fight back. When I started the game for the 1st time, part of what I used to help draw my friends is this story. I didn't really know what he was at first, as I never saw him heal. So, I approached, seeing if he was friendly, as he didn't seem to want to attack me. After a few moments of me trying to interact with him, Bonk! He smacked me on the head with that wand. I was a little aggravated at the time, but moments later, I realized how hilarious it was. Keep his priorities on healing, and have his AI only fight knights when he's cornered.
Develite Yes-Man: I don't know what this guy does. He poses absolutely no threat at all. He doesn't fight, and he turns into an over-timer once his boss is killed? Perhaps giving him some sort of ability to contribute to the fight might help? Healing, perhaps? I read somewhere that healing was his thing, but I've yet to see him heal anything.
More Clockwork Bosses: We seemed to have capped at 4, which is understandable... But every single Clockwork boss, Snarbolax, JK, Roarm's, Vanaduke are all accessible via missions. What if there were some bosses that weren't? That were only accessible via the clockworks? What if alternate versions of the current bosses were available at different teirs? A weaker Vanaduke at T1, or an exceptionally strong Snarbolax hunting you at T3...?
On the new abilities: Since I started, we've got a few new things on the go. Sparks of life popped up to replace the HP Share system, Mist is gone, Knights can now leap, and shield-rush. The danger indicator is now missing... :< Though, the enemies have remained the same. Leap alone makes the Apocrean a joke, the enemies feel obsolete... What if the enemies got a few new things to help take us on? Perhaps Jellies could disappear into the ground, to appear elsewhere like the Wolvers? Maybe there could be something to make Chromalisks threatening? I feel that Gremlins and Constructs got the most love. Everyone else was, well. Lacking.
Other changes...
Minerals...: I miss the ability to use minerals for cash. Clans could get together and rig certain stratum’s, cause instability, and make things really random. I get that this functionality was removed, but now it seems that they're only used for food. 3 of 5 minerals are only used though... What if we included two new pets that utilized the other two crystals?
Found Rarities Bound: I think I get why this is, but man, oh man, this is infuriating to me. I want to help my friends play, but I can't share the crystals I find with them? This seems foolish to me, that a team of friends can't share these between themselves to heat up their weapons. But, I see why this is at the same time, and I won't delve into this much further. It'd be nice if found rarities weren't bound to me though.
Upgrade/Downgrade Rarities: Another suggestion regarding these. What if we had the ability to upgrade or downgrade food? Fire crystals? Orbs of Alchemy? Perhaps 2x 1 star object could create a single 2 star object? And vice versa? Once you advance further, you won't have all of these useless fire crystals laying about. With no way to sell them. >.>
Costume armor: I see a lot of really cool armor. But it's all useless to me. I like my “infantry helmet.” My winged dusker coat. I have absolutely no reason to go for the costume armor because it's completely useless to me. I feel a lot of other players feel the same way. We've got some cool sets here, so why not give them some actual function? The gold armor could be a pierce defense. Weak to Shock, but strong to some other ailment? Perhaps the iron wolf set could be strong against elemental? Sure, there's more work into figuring out a good shield to go with it all, but adding some values in a table (I hope) shouldn't be all that difficult. You've got templates already setup for other sets of armor at certain star ratings, right?
More expansion content: we have Operation Crimson Hammer... And... that's it? Still? I feel that There's boatload of potential here, we could include more expansion content, paid for, of course to perhaps expand on the lore of other monster types? Or expand on the Gremlin's hierarchy?
Client Side drops: One of the problems I have with this as well is that all drops are client-side. This removes a lot of team-play based options, in my opinion. Teams cannot split in groups of two anymore. Teams can't talk via VOIP to figure out who needs that vitapod. I can't drop vials for people anymore? This... I don't know what could have possibly drove this decision. Serverside drops! Please! The old system was the best! If you're still concerned about rarities not being proper shared, then perhaps rarities could follow the same rules as cash and heat?
That Core: Still not open?! Braaagh!!!! XD Lemme innnnnnn~
Anyway, I've still got an account here. These are just my suggestions. I'm trying to get a few friends into it, but they're finding Tier 1 to be quite easy, and a little dull. With the removal of Mist energy, the game has gotten significantly easier... And, well... there's no more E-passes for me to get. :S
I would love the idea to see Gremlin Menders whack you with the staff instead of giving you a great big hug.
I also like your idea of creating more pets to utilize the other crystals.