Ok, so I have two suggestions, and feel free to critique and build on what I'm saying.
Their are still two minerals that are not used, and I have two suggestions about new sprites. We already have and offensive sprite, and defensive/healing sprite, and a stealth sprite, so how about a pure defensive sprite. It would have no healing capabilities but maybe it could do things like bolster your shield for a short period of time. Another ability could be similar to the drakon's barrier but with 4 circling spheres and less offensive power and slight knock back and more defensive power. I have absolutely no idea what it would like but it would use moonstone to craft pet food. The second sprite I was thinking of could be a crown/treasure box/materiel spite, that could have abilities such as making monsters drop more valuable coins, slightly increasing the chances or things like sparks of life and orbs being dropped from boxes, and increasing the rate of more valuable materiel drops. This one could look like the original sprite that Biotech Morlin has, and would eat pet food crafted from Valestone. Or since it's robotic be powered by Valestone that needs to be larger as it upgrades. The defensive sprite may further force knights to choose classes, (This sprite making people be a tank, the same as Drakon is mainly for strikers and DPS knights, and Seraphynx is for support knights.) which many people disliked about the sprite update, and the reason so many people like spiral knights, the classless, go-your-own-way feel lacking in many games. To combat this maybe make sprites cheaper, but then the more you buy the more they cost. People are annoyed Knights are forced into classes by having to choose a sprite early in the game when they don't have enough knowledge, but this way they can buy a second one withough breaking the bank if they really feel they made a mistake. Maybe the second sprite you get is only 800 ce (half of what they cost now) with it going up 300 ce for every spite after.
My second suggestion is to make Moorcraft Manor and Emberlight somewhat more like Haven. Obviously not with all the emenities that Haven has, but with an auction house and a few more things. I heard that Emberlight and Moorcraft Manor used to be like this, but they changed it since all the advanced players never went Haven and it was only newbies there. I don't know if this is true but to make sure this doesn't happen, make it so the only way to get into the Moorcraft Manor and Emberlight that have other players outside of your party and an auction house you have to start, say 10 depths above. If you just start at Moorcraft Manor or Emberlight the auction house is locked, and it is just your party, the same as it is now. Maybe you could make clockwork terminals like this but withought the auction house... I don't know about that one but you get the idea.
Thanks for listening and add one with your own ideas.
The problem with a pure defensive sprite is that defense isn't as nearly as important as offense in the game. the sprite would be overlooked.
a more loot sprite could mess up with the economy. you see, ce prices are very delicate. we have seen that some changes to the game and just some promos have make the prices spike up to 10k. material drops should be ok, just not crowns.
less ce for sprites on early purchases should be good, actually. they just need to make a vendor in the lab and make these pods not sellable.
the only reason you would want AH at subtowns is to check an auction you are following, and with your system it isn't feasible. you need to traverse the clockworks till the end of the tier, and nobody does that just to check the AH in another location. subtowns are good as they are.