Rewatched the highlights of Klitschko v Pulev, and AJ doesn't have anything to worry about. Klitschko wasn't doing anything particularly clever, just left hooks and straight rights and he couldn't miss.
Only thing to worry about is that Pulev is tough and AJ will have to avoid punching himself out looking for the finish like he sometimes does.
Pulev's style is why I think this could be a very quick night's work for AJ. Pulev is very stiff and upright, and not quick enough to avoid AJ's punches. Joshua's hand speed and athleticism will cause him all types of problems that he won't be able to solve. I can see Joshua dropping him with a straight right down the pipe at some point. Also, Pulev is nearly 40 so is even slower than he was against Wlad!
Pulev is a solid fighter technically but doesn't have much in the way of power either. I also think Wilder, for all his many flaws, would flatten him at some point in a fight.
As I said, I think inside 6, wouldn't be shocked if it ends in 3 though.