I really don’t want to be one of those guys on the Internet who spends all of his time complaining about things—we’re well-supplied with those, thank you very much—and besides, Diablo 3‘s beyond-rocky launch, moronic DRM, rickety security infrastructure, deliberately bad pacing, and overall shallowness have been well-documented by Rock, Paper, Shotgun, upon whom we can always rely for singular insight and appropriate indignation in equal measure.
But Diablo 3 really has been remarkable in its ability to piss everyone off, and that widespread, heterogeneous anger demands time and analysis. Some are annoyed that the game isn’t enough like Diablo 2 (I can re-spec whenever I want?), while others are annoyed that the game remains too much like Diablo 2 (I have to slog through the entire perversely unchallenging Normal mode before getting to the good stuff in Nightmare?). But of course, both these sets of complaints are par for the course with a new entry in a beloved series. Unremarkable.
Then there’s the problem of the campaign stubbornly following a rigid narrative structure, yet paying virtually no attention to plot, character, theme, or tone. I keep getting the impression that the game truly wants me to care about its world, and I keep waiting for a good reason to start caring, and it never comes. I went ahead and switched the game over to Spanish (which I neither read nor speak), in order to give all the faux-horror melodrama a neat little telenovela feel. I am confident that, in making this switch, I have sacrificed precisely nothing of value.

Again, though: unremarkable. Awful dialogue and wooden plotting are frankly the norm in games.
No, the more interesting thing—and the real reason, I suspect, for such widespread pissedoffedness—is that Diablo 3 is a hardheaded mishmash of conflicting design choices, perhaps intended to please everyone but ultimately pleasing almost no one.
The aforementioned difficulty level lockdown seems designed to slow players down—way, way down—while the combat itself has been significantly sped up. Progress rests heavily on loot, loot, loot, yet the itemization is hapahazard, perhaps even fundamentally miscalculated. The rune system promises tactical variation, yet the combat seems always to come down to click on that until it dies, and maybe use a potion somewhere in the middle there. Maybe. But probably not.
The always-on DRM was pitched as a way of keeping the experience balanced and legitimate, yet the serverside Auction House (which was ostensibly the main reason for the rights management gymnastics) creates at least as much statistical entropy as command console tomfoolery and extradiegetic character squinking would have. A friend and I recently defeated the Act 2 boss in under 15 seconds, simply because we’d bought our frankly ridiculous armaments from other players rather than in-game merchants.

That would be fine if we could then say “oh, this difficulty setting is much too easy for us,” and turn up the monsters’ power—but as previously mentioned, we cannot do that. Likewise, the slow pacing would be irritating rather than game-breaking if only we were barred from the rowdy upward mobility of the free market, perhaps by means of level-locks—but while we are currently mired in Normal, we are absolutely not restricted to Normal gear. This disconnect rapidly takes the game’s difficulty from trivial to insulting to laughable to, again, game-breaking.
All of which bespeaks a game in desperate need of fixes and tweaks from its fans—and for better or worse, Bethesda has proven that the fans will fix the game, no matter how broken. But in a paranoiac attempt at control, Blizzard has made the game unmoddable. In order to prevent others from breaking the game, they’ve gone ahead and broken it themselves at nearly every level, and also locked away the tools for fixing it.
And I’m still not sure why, except that Blizzard obstinately, emphatically, inexplicably wanted it that way. Maybe it’s all in service of the Real Money Auction House, which we’ve yet to see in action, but meanwhile Diablo 3 has made a whole lot of people unhappy. It will be fascinating to see how many of them stay unhappy, and what comes of that.