I think there's a great deal of nostalgia coming into play here. D2 offered pigeon-holed builds with synergies forcing you along X path to stay competitive, pigeon-holed gear forcing grinds or forum trading (Windforce bows and zod runes didn't rain from the heavens, no matter what the majority claims), pigeon-holed stat assignments for efficiency, and pigeons. Oh, and broken skills, the Lying Character Screen, repetitive endgame (kill Baal X1000, repeat), and nonsensical diluted classes with oskills, duped/hacked weapons permeating top-level play, bland copy n paste world generation, lack of gold sinks, lack of crafting options, enforced lack of storage space via charms, dull potion-spam gameplay...
I have zero doubt that if D2 was released today, it would be universally panned and forgotten. However... it was fun when it came out, and there wasn't anything else to compete with.
D3's 1.0.4 patch did get me back in the game, though. I took my barb, who was struggling to sword n board through A2 inferno, gave her an 1150 DPS 2-handed axe that I found, and started crashing through A2 with much less trouble. My WD can now pet-tank A3, which felt hopelessly impossible before. I found half a dozen upgrades in a couple days, with less than 80% base magic find. My first impressions are very good, in that it's a move towards balancing engaging gameplay with engaging metagame.