So so many things.
First off if a player has a solid offensive game and they are great defenders you will take them. Tell me, do you believe Dikembe Mutombo to have been over hyped? Or Tyson Chandler?
Secondly I looked at Bismack Biyombo, who didn't go to college, and ended up 8th in bpg, and 5th in block percentage as a rookie averaging something like 22 mpg. So... yeah... he's been what we would call effective.
Thirdly: are you retarded?! How could you possibly compare Hasheem Thabeet to Anthony Davis? I await your answer with baited breath. (Did I say that right?)