>>16369835
In terms of the combat system and skill trees and shit it was a pioneer, but yes so many years allows developers to add more to it and add ridiculous, if not bloated amounts of depth and complexity.
Plus it ensured pretty much every skill was very unique from one another.
Diablo clones tend to have many same-y spells or skills that wear thin very quickly.
Plus as
>>16369858
says. Pretty much no Diablo clone accomplishes its grimdark tone and atmosphere. The music, aesthetic (with gothic influences), dialogue, quests, lore and world, characters, overall story are very nice.
People like to meme that Diablo has no story. They've clearly never played 1 and played it thoroughly.