There are some very convincing reasons for why AB is a good fit and a good player for the Cs, but the major one against him is his contract.
The fact is, we are apparently trying to shed as much salary as possible and AB / Wallace are the main culprits left. If we want to try and sign some big FAs (D Jordan, Butler, Dragic, Monroe, etc), we are going to need as much cap space as possible. Avery is a very good player and one that most any team would love coming off the bench as the third guard, but as a core 'star' player, he doesn't quite cut it, and that is what we should be spending our cap space on.