You know, when you reach the end, you have all this AP that you can't use(Cause you're so epic you have all skills fully upgraded), I think you should be able to trade that AP for money. :D
On the skills, when they're like, still in mid-air, and haven't hit the ground yet, the should still do damage on air-borne units, like in the Goblin Challenge. + if you agree.
Have a firm foothold on the ground? :P