How exactly is Zo better? He isn't a better passer, rebounder or scorer. Shot blocking is his only advantage, but I'll still pick Dwight over him as a defender. He covers more ground. At best it's a toss up. I'm talking about 2011 Dwight by the way, not the current version.
They are both on the same level in my book.
look at the differences in competition. Zo played against tougher comp, what centers today does Dwight have to worry about?