Would be a strange choice by him to go to City. That is not being disrespectful to City.
Juve are a significantly bigger club than City, as are Milan and Inter. If you were going to leave these type of clubs for football reasons you are more likely to go to the likes of Bayern, RM or Barca. Though, I doubt he is a RM or Barca type of player in anything other than he has become a big name. Bayern would be a good move for him.
From what I remember at United, he was certainly not ready for first team football. Has done well at Juve, but it would help any talented player having the likes of Pirlo and Vidal next to you. Juve will be mad to let him go, when they have already lost Tevez and Pirlo.