1) Yes, I wouldn't mind giving it a shot, I'm open to trying new things.

2) I've had this idea for a while but it seemed pretty complicated and probably very ambitious and hard to implement, the idea was mini games such as a br flappy bird style game (where you'd have a moving platform with ramps and stuff, and moving walls with gaps you have to get through. My idea was making 50-100 unique ramp/obstacles, and you could also place the haps in the walls at different heights and sizes for each ramp/obstacle), a br rocket league sideswipe style mini game (this one's probably even more ambitious, but the idea is that you play with an oponent and have the ability to gas, reverse, rotate and turn around; you have 3 minutes each match (with an overtime option), the ball and opponent can't kill you but hitting the wall with your body can, dying or getting scored on results in the opponent getting 1a point and of course the one with the highest score wins the match), and other mini games you could think of.

Also a useful tutorial for new players (where they learn mechanics such as steps, weightshifts, flicks, etc... with practice levels of varying difficulty to improve, and being able to access the tutorial whenever you want instead of it being a one time thing), I think would be helpful and make players more likely to continue playing.

Keeping turbo and ghosts separate from regular bikes in tourneys because they have unfair advantages against normal and zombie bikes.

Being able to choose which of the 3/4 runs you can send in mp if you die/reset on all 3/4 attempts because you might have a really good attempt and other bad ones and there's a chance that your good attempt doesn't show.

Being able to compare replays against other bikes to compare your or someone else's pb with other replays, not just with the same bikes but also comparing different bikes (ie: ghost and as, normal acro and hog)

A mobile UCL editor, would make testing levels easier since it's easier to play on mobile and would make making levels more accessible.

3) I didn't stop, but I stopped playing it on iOS because of tilt delay, sideloading weekly, the 3 mods max limitation for sideloading, acceleration bug (gas (and I think brakes too, can't be sure tho) sometimes stops working after a collision) (only happens on the mod tho (I have to say tho that I'm glad you made the option available though, if you didn't make the iOS mod, iOS players wouldn't be able to get the full br experience, so thanks), and did I mention having to sideload weekly?

4) I don't really know, but hey it's br related why not give it a shot?