You could definitely play diablo 2 with controller with the right maping. The person who first introduced my mom to diablo 2 was actually a paraplegic man she was a home care nurse for. He didn't have enough motion to use keyboard and mouse properly but he did have just enough finger control that he could play by holding the mouse upside down in his hand and rolling the ball of the mouse with his thumb. That's practically a joystick at that point. Apparently he was also pretty damn good.