With the CBA rules, draft picks have more value now. You get young talents capable to contribute in the team and most importantly you stay away from repeating luxury taxes. Sully is the most valuable player salary cap wise. Obviously you can't afford to trade this kind of player.
DA has to prepare for the future next 5 years with no PP, KG, Doc and Rondo at the end of his career. Nobody will come to Boston through FA so you have to find a way through trading and draft. The only choice is to develop players. If think what will be good to do is to develop our 3 china men till February, hopefully they will be good chips for trading.