Chief forbrains, do you believe being 7 feet tall has anything to do with being a force in the paint? McDyess could never guard Gasol effectively. If he could get his shot off anytime he wanted on Duncan, sticking McDyess on him would have made this series a sweep in favor of the Grizzlies.
I can see it now; Gasol putting up 20 & 10 with McDyess sticking his hands up in a futile effort to contest his shots, while Randolph pushes Duncan out of the paint to put back anything Gasol misses; Then if you have Randolph being guarded by Duncan, he could just face him up, or attack him off the dribble, and get him in foul trouble. Thus, taking our most important defender out of the game.
It would be a disaster...