It is with a certain amount of dread that I put my two cents worth in here...
Putting aside the various negatives (which seem to be quite a lot), lets just look at this guy from a needs basis.
Right now, as I read the NHL stats, Vancouver is tied at the top of the league with Montreal at 44 goals (Edmonton is at 42). Vancouver is also tied at the top of the league with Ottawa at 48 goals against. Scoring is not really the Canucks' biggest problem atm, but keeping the puck out of their own net is (yes, please insert the "whoa, well they only got 1 goal in games vs Montreal", or "the high goal totals are because of the Ottawa games!" comments here).
Inserting a guy who potentially increases goals for, while also (potentially) increasing goals against does not really help this team resolve their issue.
Deangelo's cap hit also does not help this team, and I don't really see the Rangers looking to help anyone improve their cap situation (ie. accepting LE in a trade from Vancouver). I expect that they would want some sort of asset in return as it seems that it would be cheaper for them to buy this guy out rather than hand him over to someone else.
Taking a look at the negatives which come with Deangelo, his baggage/history and the likelihood of him re-offending (based on past history), combined with the money costs and on ice performance issues, makes him (imo) worthless to this team.
regards, G.