I actually wouldn't mind a straight Ray for Mo Williams deal with no draft picks or other players involved. Right now, I think Mo is a better fit for this roster, as the Celtics desperately need his scoring bunch off the bench. It'd be nice to be able to rely on a guy bringing shooting and double digit scoring night after night off the bench. Plus, the Celtics have looked their best WITHOUT Ray in the lineup, their most energetic and dominant defensively. In addition to Ray slowing down on offense, his defense just hasn't been very good this year and he also gets beat to a lot of loose balls. It was nice having Pietrus' defensive energy and speed in the lineup to balance out the age in the starting lineup.
After this season, if the Celtics wanted to trade Mo, I think they'll be able to find multiple suitors. He shouldn't be that hard to move. And if they wanted to keep him, well, they're going to have so much salary cap room that I would prefer keeping Mo on an one year as opposed to signing a bunch of undesirable guys to longer deals just to meet the cap minimum.