Looking at the roster as it stands now, 3 of the 5 starting jobs are pretty much fixed:
PF/C - Andrea Bargnani - I seriously doubt BC will think about trading his boy right when he seems poised to become consistently good
SF - Hedo - BC will give Hedo another chance. And no matter what you think of his poor performance--this would be the worst time to trade him b/c it would be buying high (last yr), and selling low (now)--not the best market move
G - DeRozan - This guy is expected to be the future, and isnt going anywhere.

So this leaves the PF (which is fixed if Bosh resigns), and the PG position.

PF - Resigning Bosh would clearly be the best move (though it leaves the starting unit pretty much as is). But I think a sign and trade that nets David Lee wouldnt be so bad -- it would provide a solid if unspectacular inside offensive presence, and will make up for Bargs less than stellar rebounding (I would argue Lee is a better rebounder than Bosh)

PG - This position is where real improvement can be made. The raptors are in a position of strength here for trade value. I think if BC can pry away Devin Harris from the Nets, this would be good. Harris' stock is low right now, but I think he still has potential to be really good. And the nets seem set to get John Wall. This option will be more viable after the draft lottery when we know if the nets pick no. 1. Other than this, what PG will give us production better than the two we have now?

In sum, I think we're pretty much stuck. Im looking for BC to pull some magic here. Thoughts?