For me, the ideal diablo-clone/arpg would be another game like Dungeon Siege 2. You'd have a party, so you can enjoy the autism of building however many characters you're allowed to have. Instead of having 50+ enemies on screen, there would be more tactics involved. Plus, I would get rid of the tiny incremental upgrades of +2% fire damage.
I'd try making it myself, but I cannot into 3D modeling.