Not sure how diablo works but the big difference is you move with the stick rather than clicking where you want to go, and you get a set of action rings instead of bars.

Imo it's not bad, lets me play away from my desk after sitting at a computer all day for work.

The only thing that really annoys me is picking up small things directly from the overworld... You can scroll selectable items with the d-pad but you have to be within a certain distance and the order of things changes when your character moves to pick something up.