Now when I see people on this forum complaining about stats, I ask mysefl, "why?"
Well, why do some people prefer games with stats?
They act as a represeantation and definition of the character in the game world. In a carefully designed system, stats determine the basic physical/mental capacities of your character and pave the way for a further refinement through skills/talens/perks/whatever.
Optimally every stat has its use. Depending on your character not every stat may be equally useful, but they all should give you something tangible in return (one game that did it reasonably well, imho, was Divinity 2, where putting some points into "out-of-character" stats was actually useful):
Strength might determine damage output and carrying capacity, Dexterity to-hit and evasion, Intelligence mana and magical abilities, etc.
Therefore one might say that stats provide an certain layer of complexity in tweaking your character to the task at hand (killing things) and/or help to identify with a character (because it's your character, you build it and it's fairly unique).
Now, are they necessary in an action game like Diablo? Perhaps not i(f you are fine with giving up the most important rpg aspect), but they have been part of one of the motivational forces in past Diablo games, i.e. character advancement through level-ups. It seems that in D3 this has been mostly replaced with item-hunt and grinding (both of wich were present before, only now they have become even more important).
I understand why people want skills and stats, no problem. Throwing out skills and attributes in a deep ruleset such as for example dungeon and dragons would suck, as it is designed to accomodate a set of diverse play styles, not only power gaming: Much of the fun in DND lies in trying to balance the skills out within a group of adventurers to try to play on each others strength and weaknesses. Now if diablo 2 were a party based non-linear choice and consequences deeply implemented in its attributes RPG, it would not be fine to remove this, as it would remove the soul of the game, but it wasn't and it nor diablo 1 or diablo 3 has never ever been marketed as such. It's always been marketed as a hack-n-slash action-rpg (or action game, if one insists on making that arbitrary distinction) and that's what it is. It's fine to criticize a car for having bad handling, but criticizing it for not being an air-plane is just... weird. And while it's fine and dandy that Divinity 2 implemented non-combat skills, I don't think it necessarily should be implemented in diablo 3, for all their similarities, they are after all, different games: Divinity 2 was a little more about role playing, while diablo is all about monster slaying, both are fine.
I can see the argument that getting to distribute 5 attribute points each level gives a level of complexity, I see it, but I don't really agree with it. To me, attribute-distribution in diablo 2 was something that was just... there. Everytime I leveled up I would do so, not on a whim, but according to a guide I had read to get the most of out of my characters, and I KNOW I was not the only one. By the nature of the skill system, there were only one right way to do it, and being designed for online, it was naturally designed for min-maxers in mind, so with a few exception, any deviation from the right way to do it, would eventually turn combat (and combat is essentially what diablo is all about) into a slow grind, where you die a lot, for no reason and for no gain. Now let me try to elaborate, by presenting the following scenario:
Imagine, in a parallell universe, that in diablo 1, you could twitch your ears with the 'wasd' keys. 'w' would make you twitch your ears forward, making it easier to make out sounds from monsters coming from the direction that the character is facing, 'a' would make it easier to make out sounds of monsters from the left, 'd' from the right and so on. Imagine now, that this got carried over in diablo 2, but was removed in diablo 3. Now, surely there would be an outcry. And one could argue that the twitching of ears made the gameplay more complex, but at the end of the day, it would simply be a feature that is there, without much purpose, because again, diablo is a hack-n-slash game, not a stealth-sneaker. It doesn't matter at all if you can hear better which direction the monsters are coming from, it's all about monster slaying anyway.
Finally, it might be true that has become more about item-hunt and grinding (was there really more to diablo 2 than that in the long run?), I will reserve judgement untill I see the final product. It does seem to me, however, that they have for the first time really nailed the impact and and satisfaction of mindless monster slaying though, though this might certainly also be wrong, I have not played the full game yet, nobody has.