So from the Sixer's perspective, they can have:
Mudiay, Noel, Embiid (just make the pick, assuming Russell is off board)
or
Smart, Okafor, Embiid plus stuff from Celtics (assume they trade us Noel)
or
Smart, Noel, Embiid plus even more stuff from Celitcs.
I can see it from Philly's perspective but I don't think (hope) DA would sell the farm for this. Noel or Okafor do have more value than Smart but I like Smart. How much of an upgrade is this for the Celtics? Not enough to sell the farm I don't think. Now if Smart isn't involved, different story.