I agree about Gibson not being a natural PG, especially at the NBA level. I see the situation somewhat like this: The Cavs get a natural PG somehow this offseason (having made the finals, they will be an attractive destination for FA's and someplace people 'want' to be traded to) and play 3 people at two positions basically, with PGTBD at the 1, Sasha at the 2, and Gibson rotating between the two positions to spell them off the bench, similarly to how they run Gooden, Andy, and Z at the 4/5 position, with Z being the only 'true' 5.
Starting line-up next year would then look like:
1. PGTBD
2. Sasha/Larry
3. LB23
4. Gooden
5. Z
1/2 Sub. Boobie
4/5 Sub. Andy
That's a pretty solid line-up IMHO, especially when you consider it's basis around that guy at #3