I hope you people realise that the game design is lead by Jay Wilson. He is not known for making carbon copies of previous games, but he loves to change pretty much all the mechanics in a game. Also, its not the WoW team who made this game, but the influence is certainly there.

He turned RTS conventional designs upside down with Dawn of War 1 at Relic, with emphasis on map control, squad system, cover and morale system. Then, a few years later, he changed the RTS formula entirely again with Company of Heroes by adding features like destructible environments, directional armor for tanks, command tree, even more emphasis on map control and so on.

Due to Jay's previous work on Relic, i never expected that Diablo 3 will be exactly the same as Diablo 2. He likes to change things around, a lot, by removing some of the defining features of a ARPG like stats allocation and skill points. As far as i know, Jay Wilson wants to innovate the genre, not keeping the ARPG stale like how boring most MMO are these days. Also, in my opinion, this is a very healthy sign for the ARPG genre, as pretty much all major ARPG developers are trying to break away from the old design.

With my 20 hours of playtime in Diablo 3, i say, he did a pretty good job.Most changes like the "stupid" skill unlock tree or no stats allocation has been pretty good changes for me so far, even though it seem a bit dumb downed on paper. In practise, it works very well, at least for me. I have also enjoyed the art style, which looks whole lot like a faded watercolor paint drawing, while the atmosphere is awesome. I'll take back the complaint on the art style is not gritty or Diablo enough.

I still have my criticism on the game, namely the Always Online shit with lots of sugar coating. It's annoying. In addition to that, i felt that the game does have some serious problem, especially in terms of longevity as the Jeweler and Blacksmith could not offer enough depth and longevity as Diablo 2's gambling system or how the archaic skill system. Something is missing here, but i dont know how to fix it.

If you are really disappointed with Diablo 3,  buy Torchlight 2 then because the game feels hell lot more like Diablo 2 than Diablo 3 to Diablo 2. And the game is made by some of the founders of Blizzard North/ Condor Games. The pet and skill system is pretty amazing too, as far as i can tell in the beta.

Or just wait for Grim Dawn, if you want some really difficult ARPG game, with some new innovations like faction system, open world design like Skyrim and unforgiving gameplay.

I pretty much pre-ordered/ bought all 3 of them, because each of the game offer something radically different on the table.