I think the Celtics need the backcourt depth. More and more teams are rolling out 3 guard offenses, small ball lineups, and lineups with large SFs playing PF. I think the Celtics, in order to match up with those teams, need the depth.
That said, I like the trade idea.
We have enough depth, Green can play SG without any problem (in fact it probably helps us on offense). We already went into a postseason with him as our backup 2-3. Besides we wouldn't even need him if we played Lee 30, Terry 30, and Rondo 36 (and don't forget about Dooling on top of Green).
Non-issue.