Kolo is alright, nice guy and I never questioned his commitment. He certainly wasn't the best defender we've ever had but he was highly thought of from 2004-2006, being part of the Invincibles and the meanest CL defence. Campbell and Senderos complimented him well, in the same way Kos and Merts have looked decent together, despite having an opposite style of play.
He obviously didn't get on with Gallas and that ruined any chance of forming a partnership there. The time was right for him to leave and the offer from City was too good to refuse.
Legend? No.
Deserving of our respect for his service here? Yes.