Yeah there's no game even remotely close to D2 unless it is Path of Exile. It's the most accurate spiritual successor to the game. If you want dark and you want harder and more varied systems, that's the game you are looking for. Marvel Heroes is a close second in terms of systems, but is the complete opposite end of the spectrum in regards to aesthetic.
If this is really what you are looking for in an ARPG, I don't see how Path of Exile wouldn't make you insanely, insanely happy.