I'd describe PoE as more of a spiritual successor to Diablo 2. There's a lot of weird aspects of D1 which were removed in D2 and later games -- for instance, spellbooks, elixirs, and randomly generated quests.

As a concrete example: PoE's schema for items (normal/magic/rare/unique, maximum of 3 prefixes and 3 suffixes) is almost a carbon copy of Diablo 2's item system.