There is a slowly but steadily progressing engine being developed at https://freeablo.org/
It's such a shame there's no modern spiritual successor to Diablo / Diablo 2. The aesthetic and gameplay was great.
Diablo 3 is actually pretty good now if you want a successor. If you just want something similar to diablo 2 I suggest torchlight or titan quest.
Diablo 1 is tricky because it was so much closer to rogue likes (probably because originally it was one). I would love to see a game that has a more subdued and methodical pacing but with less town hacks :)