I read that Chris Mullin said something like ”you can always trade talent”, and that's why he stacked players, that maybe didn't fit the team, but would help make those trades that eventually got the Warriors to the playoffs again. Maybe his track record isn't that impressive, but he's got a point. And that was also what Ainge did before the 2007 trades for KG and Allen.
And what do we have on the Celtics roster that is tradeable? Expiring contracts, a veteran future HOF small forward, some younger players with unknown ceiling who have yet to prove themselves and an All Star pg entering his prime.
Of all these the only commodity that – right now – could be packaged to bring us a franchise player is Rondo. So anything less for him should be a no-go. Not even picks (unless it's top five), because we probably will be entering lottery ourselves from next season, and Rondo will still be very tradeable in one or two years, meaning that we will be able to put together a better package for a superstar trade, if we keep him. And if we are able to acquire one or two stars through free agency, we don't even need to trade Rondo (unless Deron Williams is one of our acquisitions).
Should we build with or without Rondo? Well that depends on what talent is available to us. I would love to keep him, and see him take his game to the next level as a scorer and with an athletic, running team.
However, Danny should (and will) listen to any offers that can get us a (potential) top ten player. But those offers don't come often, so I would be surprised to see him go. And I would be sorry to see him go for players like Pau Gasol, Big Al aso. They are a big upgrade over JO, but they will not make us top contenders (unless Pau suddenly becomes a top ten player again), and from next year they are most likely just big contracts without much upside.