If the Celtics can get a nucleus of Rondo, Smith, and Green going forward, somehow hold onto Bradley and Sully, and perhaps end up with net of a first round pick or two with the departure of Pierce and Garnett, I think they are in a pretty good place going forward.
Is that enough to win a title in a year or two? Probably not, unless there's significant development. But it's pretty darn solid playoff team that has some pieces to make improvements. And at this point, unless your plan is to tank until we hit the next LeBron (see how well that worked out for us in the bulk of the '90s and 2000s), I don't see much of a better alternative.