Personally I'd like him to stay and build around him. Having him here makes Boston a more desirable FA location.
However, if he moves, I think the Celtics have to come out of this draft with Exum and Parker as their two new cornerstones . They'll have plenty of cap room to fill out the other positions . It's also possible that Pierce and Garnett return to end their careers here as the older mentors off the bench.
PG - Exum
SG - Hayward
SF - Parker
PF - Aldridge
C - Asik or Gasol