I hope this one doesn't happen.
I was looking forward to seeing Ed Davis and Amir Johnson lock down the power forward spot next season for the Raptors.
I don't think you'd have to worry. I think they'll probably use Diaw exactly as they used Turk: as an oversized 3. They'll shift Bosh's offensive possession to Diaw and Bargnani and they'll rotate Amir and Ed at the 4 to play defense and rebound in between the softies.
I think he'll play well for them. He allows them to invert the 3 and 5 roles when Bargnani's on the court.
You can run a bunch of offense through Diaw in the post at the 3 while using Bargs as the entry passer and perimeter threat.