Here's what it boils down to, imo.
1) 'The Patriot Way' has been talked about, analyzed, written about so much these days that players simply have to know about--the mentality, the team-first concept, the 'BB's way or the highway'. When Dillon first came to the Pats, it wasn't firmly established and many felt that he'd be a disaster here. When Moss came here that mentality was well known, so people said 'if he acts up, he'll be out of a Pats uniform that day'. Chad has to know that the Patriots are run that way, that it's the basis for their success, and I think he knows going in that he'd have to change his ways.
2) Belichick and Pioli know everything--absolutely everything--about a player before they sign them on (whether through free agency, the draft, a trade), and it goes much deeper than their on-field skills. I read an article a few months back talking about their exhaustive research into a players personality, work ethic, intelligence, etc--much more than just the Wonderlic. If Belichick likes him--and not just in a 'I'm amused by his antics' way--then you better believe they'll do everything in their power to get him if the money's right. He knows who fits in this system, who he can control, and who simply wants to WIN--something that people confused with selfishness when it came to Dillon.
Bottom line: if Belichick wants him on this team, then I want him on this team. The man just knows talent and personality, and how to deal with both. An offense of Brady, Maroney, Watson, Welker, Johnson and Moss would be downright unfair--if ever the whole 'why don't you just crown them' quote is applicible, it would be with that team--and it's probably a pipe dream because of cap issues anyway, but I'm all for it if Belichick wants him.