I think for even just a couple of the reasons spelled out by Tolmie, then i wouldn't want him back at the club. FFS, i can't even bear to have him in my squad on FIFA 12 against my 7 yr old lad (i always insist on being City!). But i do agree with sentiments above. Anyone who plays, would get my backing. I'm cheering for the shirt and the club, not the individuals who play. They are transient and are commodities bought and sold by the club. Us fans are there through thick and thin, and remain the only constant.
However, the issue would undoubtedly split opinion. Tevez coming back would need to be all or nothing in terms of support from ALL of the fans. Some will want it, others won't, and there is no right or wrong. The only thing that is certain is that any division amongst the fans woul create a negative atmosphere with the media circus waiting to pounce, which would destabilise the team. On paper and in theory, yes he might seem to be the missing piece of the jigsaw, but i doubt there would ever be a sustained period of stability for him to prove his worth and how genuine he was/wasn't commited to the cause before the wheels would come off of any title bid.