My take is that, the storyline is just full of cliches and DUH moments. And the tries-to-be-but-not-scary-at-all environment that one was a big LETDOWN for me.

For people who enjoys the looting and collecting stuff, they will enjoy this game. the "hates gonna hate but people still plays it anyway" is not really true anyway, since there aren't any new alternatives (torchlight 2 is not gonna be here anytime soon), people who enjoys this sorta games have no choice but to suck up. It only mean that the game is not all that great like the hype.
That one was a real downer for me, but not like what you said. It's more like



And at Act III



That was a serious DUH moment for me.
But what everybody is saying is exactly true. D3's single player is not really a single player mode, but a multiplayer mode just by yourself that's really stupid IMO. If you exit the game halfway, then the whole dungeon's gone. If I REALLY want the whole dungeon gone, I could've just started from whatever point that I want from the menu, since they have that feature!

The separate loot for each player is a nice addition.
The still-funny logic that demons carry gold.... in hell.... is still ridiculous 
The dumbed-down Normal for insane Hell difficulty is great for every kinds of players.
The one-stash-for-all-characters is great.
The Followers story is good, but not great. No sidequests? Why build a half-way story-featureset?
The statistics system based on your item is great. So many many viable builds instead of two-three builds for each character in Diablo 2.
The limited skills is good, but again, not great. If you're gonna limit skills from 20+ in Diablo 2 to just four, you're just asking for hatred ler
The many, many merchants.... what's the point really? And no merchant side quests? (at least till Act III, since I haven't finished Act III yet)
True, and I agree. My significant other tried this game (I exposed her to minecraft before) and she LOVED IT. It seems scary for her and not for me at all, which makes me wonder, maybe it was scary for us in Diablo 2, and after 10+ years we've all grown up and got exposed to the world, that games like this is not scary at all anymore. 

Diablo 3 is not a MMORPG, but MORPG.
No persistence world but with room/session based gameplay.
like Dragon Nest, League of Legends and Sudden Attack, many people on the server but you only play with a set number of people and cannot affect the game world.

Many blizzard will make World of Diablo Online? 

---

Added on May 21, 2012, 1:55 pm

ya.
I played D1 and D2 and found D3 to be a good sequel.
It was an improvement over some of the annoying things in D2.
Sure D3 is dumb down abit for mass market, but the change encourage player to adapt new strategies and become more flexible.

D1, there's no outdoors.. it's catherdral all the way down to the crust of the earth and then hell

implementing RMAH is a win win situation since there's gonna be a pvp function, ppl will want to get better gears to stay on the competitive edge. Like it or not, RMT will happen regardless so blizzard might as well give players this option which provides a more secure transaction and earn money while at it.