Diablo III sold extremely well initially. The game then drew some attention from both those who loved it and those who disliked it. The forums seem replete with both excessive praise from those who liked it and vitriolic condemnation from those who didn't. A marked polarisation. Since I haven't played the game obviously I cannot state any personal preference either way.
Before I continue I should point out that I'm in agricultural research and spend a lot of time in areas without internet connectivity (Yes Virginia, they DO exist!). Therefore any game that requires a constant internet connection doesn't work for me.
Diablo I, Diablo II and the L.O.D. expansion (which I'm still playing) rapidly became, despite some problems, the standard against which all similar games (and there were many) were judged. Hence many players of the early titles felt that Diablo III would follow the same general path. According to its detractors it has failed to do so.
This doesn't mean that Diablo III is a bad game. It indicates only that many people who purchased the product felt that the product should have been other than it was. They were disappointed and felt betrayed.
There are apparently issues with botting and with players of questionable integrity. These problems will always be a feature of any online game. If there are opportunities for profit then people will take them. Offline play or LAN games are mostly free from this sort of problem.
How and why?
Well, despite what many people claim, they don't like large amounts of change. They want the book they buy to be pretty much like the others in the series with maybe a couple of extra chapters and a new cover.
This brings us to the point. The developers of Diablo III have stated that the game they produced was the game that they wanted to produce, but the question is did they produce the game that the client base wanted to buy?
Initial sales figures are not a reliable indicator since a proportion of those sales would doubtlessly have been based on the high reputation of previous titles in the franchise.
The mantra is client focus, client focus, client focus.
Since I don't support either faction I now expect attacks from both.
IMO, anyone who buys any game based solely on the dev's reputation, the game's prequels or alpha/beta footage rather than waiting for reviews, demos and/or coherent, thoughtful feedback from purchasers (good luck with that one) regarding the actual released product has only themselves to blame if they don't like the result.
The fact is that D3 sold incredibly well, and if that was a poor reflection of the game's actual quality, then that's entirely down to consumer impatience/irresponsibility. The sales figures for D3's expansion will be the truly telling statistic... hopefully. Or maybe I'm under-estimating people's ability to let hype separate them from their money.
I'm personally in the camp of the game is what I expected it to be, even though I played D1 and D2 religiously. I fully expected there to be vast updates after launch, just like D2 had. I also expected the game to be far different from D1 and D2, and I'm glad it is. If I wanted to play D2, then I'll play D2. I'm defiantly in favor of updating and adding to the game, which because it's Blizzard I think they've proven to the player base they want to and will continue to upgrade the game.
I also think there's an element of rose tinted goggles when it comes to comparing it to D2. PvP wasn't that much fun because it mostly resulted in griefing. MF runs consisted of two minute games where you skipped an extremely large portion of the content ( trash, white mobs, elites, champs, breakables) zerged down the boss in mere seconds thanks to the huge level difference between players and bosses, and then left. If you weren't joining peoples games to PK them or doing the standard MF run, you were probably leveling another character by doing tristram runs / tomb runs / baal runs. Ubers were added after the expansion pack, which was an awesome addition. When looking for loot, I will say D2 had a couple things I hope are added to D3; Runes, more gems, jewels and charms. I have complete faith most if not all of these types will be added eventually, as they added an extra level of fun with drops.
The whole point of my paragraph on D2 is that it WAS fun, but it also had almost no competition. There were a lot of problems with D2 which I believe D3 has all but fixed.
TLDR; D3 is a great game, which is only going to get a LOT better with the coming patches and expansion pack(s).
It's a funny dichotomy: most game critics (and a lot of gamers) want to see a Blizzard game innovate a genre, create entirely new ideas that will revolutionize gaming - when it doesn't, it gets downvalued (with D3, most critics actually liked the system changes a lot and considered them innovative); andthen a lot of fans just want to see the previous systems that "worked" fleshed out, and an experience that is as traditional as possible.
Really hard to please everyone SC2 and WoW suffer from the same fate.