A rant on Dungeon Siege:
Diablo II was a much better game for many reasons, which I will explain below.
1) non-linear world. Diablo II questing didn't feel like you were following one road. While you had a goal that you were striving towards, you weren't forced to walk one windy path with a few "extra places to go." Maybe I was expecting too much from DS, but I expected a larger world with more variety in the terrain and more ways to go. DS was just too linear.
2) Diablo II has very intruiging and interesting character classes. They all provide different ways to play, be it hack and slash or caster, or the more strategic route via the Necro or Druid. DS had a neat skill-based system, but it didn't allow enough diversity. It was too unorganized.
3) Diablo II was more immersive. Even with its 2D engine, I felt more apart of the game than I ever did in DS.
4) Dungeon Siege was too easy on easy and too hard on hard. It was too difficult to find the right balance. Diablo II had a good balance of easy and difficult areas, so you could feel like a badass but be challenged at the same time.
I personally think the best game would be a combination of Neverwinter Nights and Dungeon Siege. Neverwinter had all the good RPG elements that Diabloe lacked, but it played too slow. NWN was a blast, but a lot of the times I found myself craving the cool auras that my had Assassin in Diablo.
What I meant by 3D Action RPG was not a top down game. I'm talking 3rd person view like Jedi Knight II. With those controls (add a few moves), cool spells and special abilities that you could gain with levels AND cool multiplayer support (co-op and team-based war or something), you'd have a great game. that's what I meant by 3D Diablo game =)