I really dont see how you can say he is awful against guards driving. From what I recall, very few guards scored over him.
As for the Tyler Zeller comparison, I dont see how you can compare them whatsoever, but I will bite. I admit Zeke is not the offensive player that Zeller was in college. But remember, Zeller is nothing AT ALL on defense like Zeke. You knock Zeller, but seem to forget he was drafted in the middle of the first round, and is only a rookie. He is 4/6 against the Hawks and Al Horford at halftime right now, actually. Zeller struggles in the NBA because he is a softie. He doesnt have the physical game like most centers in the NBA, or like Zeke.
Zeke, however, is not limited on offense when you compare him to other centers that actually have a similar playing style to him. Noel and Withey are good comparisons, IMO. Zeke is much better on offense than both of them. However, they will be drafted higher because of having higher upside. Noel has absolutely no offensive game at all and people had him going #1 before the ACL.
I think he will be drafted late first/second. It depends on what type of center a team wants. I know the Cavs could sure as hell use some interior defense. I guess that we will have to wait and see, though. I wish the best to him, and could see him having a decent length career in the NBA regardless if he is drafted or not.