So, I haven't gotten as far into D3 as I otherwise would, but I am on Act 4 of normal with a Monk, and my wife and I are on Act 2 of normal with a DH/WD combo.
We both really love the game so far, and some of the Blizzard forum complaints drive me nuts.
Maybe I'm just not 'getting it', because I generally never played D2 online. To me it was a solo game pretty much exclusively. But, having said that, the complaints about itemization and the Auction House just make me sigh and roll my eyes.
The way I look at it, there's not that much difference between endless boss runs in D2 to get different epic drops each time which may or may not be useful and which the players can buy/sell/trade, and the open Auction House in D3 combined with low drop rates of really good gear from elite mobs and/or bosses. In D3 you don't have to just keep doing boss runs, and you have a good chance of elite packs dropping great stuff too, but the overall chance is just lower. Enter the Auction House, where you can exchange all that gold you just farmed for something which is better for your toon. In the end, what's the difference, really? You're still upgrading, and at least with D3 you can pick the exact item you want rather than being a slave to repetition of the same bosses ad nauseam and hoping for just the right combination of stats and effects.
I didn't buy D2 until after the LoD expansion anyway, but from what I've heard, D2 wasn't quite all that and a bag of chips out of the starting gate either.
So pardon me while I continue to enjoy D3 and look forward to future updates and expansions.