Those are all rubbish in Diablo 2, though.
Diablo 2 strengths are in its replayability and in the very diverse character builds.
Actually the stuff I listed is handled quite well in Diablo 2. It's part of why the game got a patch 10 years into it's life and why people still play game, more people than play DS3 by the way.
DS3 is not about GOOD ACTION COMBAT either ... it is definitely in the same genre as Torchlight ... this isn't Ninja Gaiden.
Enemy variety and AI is good in Diablo 2?
HAHAOHWOW
No it isn't Ninja Gaiden, it's a BG:Dark Alliance style game.
BG: Dark Alliance is an action rpg like Torchlight. What planet are you from? Torchlight just has ultra gimped multiplayer as in they gimped it out of existence which is a huge negative against that game. The next step up in gimpy multiplayer is DS3, you know hobbling along with a cane telling the youngsters it's cool to only have one multiplayer mode cause that's all gramps needs!
EDIT: I'm willing to bet that enemy variety in Diablo 2 >>>> (that's much much much much greater btw) DS3
In Torchlight, or Diablo, or Titan Quest you don't have fine control of your character. You don't have active dodge, active block, combos. It's the reason why continuous attack works with the first games but wouldn't work with Dungeon Siege 3. And it's why Dungeon Siege 3 ends up in a very different genre. The player's manual dexterity is much more important in DS3 than in Diablo.
Dungeon Siege 3 and Dark Alliance work as lite versions of Ninja Gaiden or Devil May Cry. You may not enjoy that sort of gameplay, but it is what it is.