I have no idea if Balotelli will ever fix his mental problems, if he'll become great or not and if a change of environment will help, but what you forgot to mention is that he is 19 years old.
You're what...25, 26? How much have you changed from the time when you were 17-19? I was ready to do any kind of stupidity that will put me in huge trouble when I was 19. Now I'll chicken out at the very thought of doing some of the things I was doing.
Sure, there are guys like Martin who were wise old men even in their teens

P) but the majority of us were brainless kids in our teens, becoming more mature as time goes on.
Balotelli may or may not become wiser and mature. There are millions examples when age didn't really help become wiser. But there are 10 times more examples where people did change.