I think Bargnani has reached his potential, so its up to BC to decide what to do with him. He needs to have two dominant rebounding/defensive players on the floor with him, to cover up his liabilities. Davis/Wright/Alabi/Ajinca All have that potential, but the emphasis is on potential.
If the Raptors can get lucky and draft Kyrie Irving, then they should look to trade Calderon when he has value. Otherwise the Raptors need a more polished version of JuJu, to start at the three and a veteran big man to plug next to Bargnani, like Nene or Chandler.
I'd rather develop the bigs that we have and look to find a good defensive three, that can start and a point-guard to replace Calderon and push Bayless.