I don't like the Diablo and Diablo-esque games because for me they combine the worst traits of a 3rd person rpg and the worst traits of a multiplayer fps.
They take killing with no plotline from the mmofps, combine it with the anti-submersive and extremely monotonous fighting system used in 3rd person rpgs.
so for me it's just repeatedly clicking on monsters just for the sake of doing so.