I mean it seems like the high cost is supposed to serve as incentive to collect stars and level up. Every level up decreases the cost of rolls by 5. I'm level 30 and I hit the minimum cost of 80 coins awhile ago. My issue with this is that it also incentives saving up your coins and not rolling until you're about level 25 which I think is where you first hit the minimum. I'm kind of a gacha addict so I'm fine with the random chance, but I can absolutely see why it would annoy people.
Your second point is something I absolutely agree with. It'd be great if we could roll multiple times if we have the coins. You get 1500 coins a day from dailies and it'd be helpful to just be able to blow through them all at once.
More animations per character would also be nice, but given the number of characters he's working with I don't mind it. I'd rather see new characters than better animations, personally.
Also if you're still having trouble with long jumps my tip would be to press the duck button and jump at the same time, or as close as possible. I agree that the controls could be better, though.