I've heard Billy Tubbs say that if a kid is really 6'9, then that is plenty tall enough to give you what you need for D1 college play. I would agree with that statement.
This statement notwithstanding, Billy would play better shorter players in the post, William davis, david Johnson etc, than taller and less talented tall players. So, he didn't always play at least one tall kid just for height.
Coaches vary on this issue. I have always sort of been in the Eddie Sutton camp. You simply have to have at least one big, and he had his bigs compete only among themselves for the post position. He didn't force big Country Reaves to compete for center with a more talented 6'6 guy for center. Billy would have played the shorter more talented player. I viewed this as one of the few weaknesses of Billy as a coach.
Tall kids are the last to develop -- period. Always have been and always will be, and for lots of reasons. If you don't play them, they never develop. I would rather have billy as coach than Eddie, for many reasons, but I think Eddie's approach to take his best big and play him, ultimately developing at least one big, was the best long term approach. Created a higher ceiling in my view for the team. Both thoughts on this issue are reasonable.
All this being said, all things being equal, tall beats short in basketball.