I won't attempt to make Aqib seem like a victim to circumstance with his run-ins with the league and the law. He is most certainly a gamble, and we should all keep that in mind.
HOWEVER - Coach Schiano did talk about Talib earlier in the season, saying how he's been a good soldier for him and how he hoped things had been turning around for him. Then came his Adderall suspension, of which Aqib himself acknowledged was a mistake.
We all know Bill and Greg have a great relationship, and I do not believe for a second that this trade would have happened if Schiano believed Talib couldn't change for Bill or fit his system. Bill has recovered multiple character issues in the past (Harrison, Dillon, Moss... Haynesworth didn't wanna play, and Ocho didn't know playbook). I'm willing to trust in his judgment.
With that said, what Aqib Talib brings this team is a potential shut down corner. When Talib is "on", then nothing gets by him. But consistency is an issue with Talib, as is his technique at times.
If we can maximize his strengths, perform well, and be a good boy to Bill, he MAY just find his stay in Foxborough longer than 7 weeks.