Okay, two people referenced that link in as many pages so I just had to read it and sure am glad I did. I think it finally helped me pin point exactly what it is that D3 seems to be lacking for me. Personally, I enjoy games that take 5 minutes to learn and a lifetime to master. Needless to say I like chess, but games like Diablo 2 also fit this. Getting started in Diablo 2 is about as simple as it gets. Run outside of town, start mashing your left mouse button, watch things fall over, loot, rinse, repeat. What, people play this for years!? Of course it's no long after that that the game starts showing its true colors and you find that even after playing for years you will invariably find yourself learning new things, coming up with new character ideas and generally just learning.
And I don't even mean that in the sense of well unless you've memorized every inane chart at Arreat Summit then you surely have more to learn. Or "Oh you don't know about the strafe bug? Hahaha, why in the world would you get your IAS to 130? The breakpoints for 4 and 3 frames are effectively identical! Wow, noob!" That isn't good design. It's annoying and cumbersome. I'm talking more about normal gameplay things. For instance anybody who's played D2 long enough has probably thought about trying to combine damage taken goes to mana, mana shield, and reduce damage to create a near invincible sorceress. It's fun, it requires thinking and the answer is surprising and leads to more fun and interesting ideas.
Now D3 seems to ostensibly have the same sort of system in place. But that post you referenced mentioned something that very likely does seem to be the case. The designers seem to have tried to take the 'what if' out of the game. That definitely seems like a great idea in general but in this case they seem to have done so to such a degree that instead of 'what if' I'm left with no real sense of curiosity at all. I looked through all the classes passives and the lists of skills we had available. There were lots of interesting skills but nothing really left me with that sense of wonder and awe that Diablo 2, even after years of play, constantly managed to. The skills, for the most part, seem very safe, modest and as a result ultimately not particularly interesting - even if there are a billion of them.
Again it's a good game, and it has done a lot of things right. The attacks really do feel like they have 'weight' and modifying of some of the excessively annoying and esoteric aspects of Diablo 2 like crafting are huge improvements. But I fear they've gone a bit too far here. It's like they were trying to make a nice soft drink. They started with Diablo 2, some murky and excessively rich opaque syrup. It needed to be watered down quite a bit, but they mixed up the ratios and have now left themselves with just mostly transparent sweet flavored water. Unlikely to offend, but also not something you'll probably have too many people coming in day after day, year after year for.