Ok, I have a few ideas, ranging from silly to "Hey, I'm trying." All of these are at least semi-serious, though.

First: This isn't my idea, I just want to mention it because it's a really good one. Have the ability to sink crowns into a piece of 5* equipment for a chance to infuse it with a UV, or if the equipment already has a UV, improve it or spin the wheel for a new one. I don't mind if it's viciously expensive, like 20-50k crowns per shot, but it'll allow us to improve our equipment, and let us remove useless UVs. (Attack Speed Increase on a bomb? Improved damage to Gremlins on a Hail Driver?) It'll also improve the CR/CE ratio, since crowns will have more value.

Second: Sell refillable mist tanks. I got this idea from Mega Man X, actually. There are casual players out there or just plain busy people who might let their mist gauge fill up past 100 ME. Why not let the overflow siphon off into a Mist tank that you can use to refill your bar? This would be a popular option for people who have other things going on and can't play every day.

Third: This is a weapon idea. It's a board with a nail in it that functions as a sword and deals normal and piercing damage. Oh what the heck. Take this idea and run with it! Make a Hobo armor set! The Helmet is a cooking pot or a colander on top of a paper bag! The armor is a bunch of frying pans and toasters strapped to the knight's armor with duct tape! You can use a Health box lid as a shield! No, but seriously, I would use the nail board, especially if it upgraded to 5*.

Fourth: Dodgeball minigame. Players throw pots at each other. Add fire pots and oil pots for strategy, or devise poison and stun pots for even more strategy. Costs crowns to play. Winners get a random token, or a special token for a dodgeball weapon/armor set. Or the nail board from above.

Fifth: A gun that shoots bees, and a bomb that is a beehive. "Bullets" have slight homing abilities. Elemental/Shadow alternate upgrade paths. You know you love it.