Until Rondo's back, though, Pressy's the one guy that I really trust can get the ball upcourt against pressure. Everyone else we're asking to play point guard in Rondo's absence is really a 2-guard (or small forward) playing out of position. Turner's got decent handles, not sure about Smart yet, but still - it's nice to have a legit, ballhandling PG somewhere on the roster.
I've lost track of the roster, though - are they in a numbers crunch? It is really an issue at this point?
He's certainly not someone I have great expectations for long-term, or someone I'd be upset about if they HAD to let someone go. But, I've see Celtics team struggle in the past without an actual point guard to play the point. Not a guy I'd dump just to dump.
EDIT: Do people want Pressy gone to free up a roster spot for Powell? That doesn't make any sense to me, we have too many power forwards as it is.