I think Willis has all the skills necessary, his body and defense just weren't ready. If he works hard I can definitely see him getting some PT. FWIW, I keep seeing Rex Chapman say Willis is the only 3 on the roster and expects him to start next year.
Also, Hawkins is a great on ball defender and if he can get a jump shot he will earn some minutes (not a lot I'm sure). Good thing about Hawkins, as we saw with the tournament, is he is always ready to play and whether it's 2 minutes or 20 he gives it his all.