The problem with Willis is incositency at pass blocking. When the guy blocks a blitzer he stops him on his track. That block against two Phinz was textbook blocking. Amazing one. In the next play of the very same game, he left a blizting safety get the sack (leading to a fumble that the refs overruled because the QB safety rule). I could only scratch my head after that one. Granted he was going on out to run his route but he didn't even slow the guy down, giving his QB time to throw it away or sidestep the pressure.
I mean, there is no doubt the guy can pass block, it's his consistency that it's at stake.