Currently the spin of the wheel gets you one of the following: a tier-leveled pickup, a tier-leveled heart, 5 crowns, 10 crowns, and 25 crowns. Are you serious? 5, 10, and 15 crowns? I get more from a silver-gold consumable. The entire thing seems like a way to lull the player into thinking "ooooh, maybe I'll get the box THIS time." and instead of giving them things that would be useful as an alternative you give them absolute crap so the crush of not getting the box hits harder, and if they ever do get one they'll be satisfied longer.
TL;DR My proposal for actually useful rewards:
- 10-mist mist tanks (little mini tanks, don't know if they exist already) rare
- at LEAST 100, 500, 1000 crowns. I can't reiterate this enough, 5, 10 15 looks like it was accidentally left in during development. Fix it
- Tier appropriate recipe rare
- Further note: Recipe I don't know. As you move up in tiers the current tier becomes more rare, but you can still earn lower tier recipes. Example: Tier 1: 2% chance of 2* recipe. Tier 2: 3% chance of 2* recipe, 2% chance of 3* recipe. Tier 3: 4% chance of 2*, 3% chance of 3*, 2% chance of 4*, 1% chance of 5 star
- Keep the tier-appropriate pickups, they're not all that bad
- Don't give me a heart when I have a full bar, come on. And if you do, don't make it tier-level BS, fully restore me
- BONUS HEAT! Right now bosses are the hardest fights because they're bosses but they yield less heat than any other map, it doesn't make sense. Currently it's hardest fight, least reward. Why isn't it hardest fight, greatest reward? I don't understand this decision
- Random item, max of 3* rare
- Random usable (krogmo booster, heat booster, trinket unlock, weapon unlock, etc.) rare
I probably left a few of the ideas I had floating in my head out of the list but that seems to me a pretty decent way to make the wheel actually useful. It's pitiful right now, it's a waste of time. If the rewards don't change there's no reason to leave the wheel in, just make the box a percentage drop from a boss or something. Don't take the previous sentence seriously; I think if you take this list into consideration and actually improve the wheel then players won't find it so pointless.
Most of your ideas are awful, namely "100, 500, 1000 crowns.". That would be the best way to break the economy.
The only thing I agree with is mini-mist tanks. That would be sweet, a chance to have your level essentially "free" without breaking the economy. Rarity on par with lockboxes.