I finished Diablo with the warrior, and yes, that was using a mouse... as using the touchscreen is rather challenging for diablo.
I've also been using a mouse to play half-life and arx fatalis...
edit: concerning Diablo, there's one anoying "bug" when using the mouse... everytime you click on an item in the inventory (to pick up or drop items) the mouse cursor jump left by what seems like the witdh of the black border. nothing too bad or game breaking, but it gets annoying fast when managing all your potions or gold piles...