I think it'll be a good move for him, he's not in Aguero's class but IMO he at Bayern he can get back to how he was before he went to City and become a class striker again. When he was in Germany, he was comfortably a better player then Gomez, and I think he might displace him if he does go to Bayern.
The problem at City was that their style does not suit him at all, and he wasn't guaranteed to start games, no matter how good he played (at the start of the season, the game after he scored 4 goals he was benched). He needs much more consistent playing time, and not coming on in the last 15 minutes of every game. It can't do any good for your confidence when Balotelli and Tevez are getting games ahead of you, even though you have scored more goals than one, and have a much better attitude than both of them.
Bayern's style will suit him much more IMO, they play with genuine wingers and will cross the ball into the box more. He's much more suited to a team like Bayern, spurs, or United rather then City who always try to play it through the middle with short, quick passing.