I really do like the game, but there are a few things I don't like at all, and I'm posting here hoping they will actually change until release. Let's start:
The current skill-system won't make people come back to the game once they have finished it. You basically play every char until it reaches level 60 (or whatever the max is) and that's it, you've seen it all.
Now, I don't wanna go back to the D2 skill-system, which was a chore as well. But at least adopt something similar to what skyrim used: leveling by using the darn skill. You should get better with your skills by using them, and that would allow you to improve even once you've reached the maximum level.
No quick travelling?
I don't know if some sort of town portals are going to be included in the final game, I didn't see any in the beta. But if the beginning of the dungeon and the town is the only place to change your skill loadout, it is really annoying not to have a fast travelling system. I don't wanna wait for 30 minutes before trying out my newly aquired spells. Also, the only place to test out your new spells is in town. Not really the best setting, given that there are no critters around to test it on... this feels really lame actually.
People have been lamenting a lot about this. I get the feeling that Blizzard is trying to hide the WOW background of its engine by adding some weird looking color layer above pretty much everything. The outskirts of Tristram look like pure **** with that blue-ish or green-ish layer on top of everything. It just looks bad, sorry. This game looks way worse than Starcraft 2 did.
Weird looking armour
The equipment you wear in this game just kills the atmosphere in my opinion. I mean you get pointy hats, glass balls, you carry books, the barbarian runs around half naked even with armour. I just don't know, but to me this makes me feel like I'm playing a mix between Harry Potter, Magicka and WOW...
The engine and graphics are unimpressive. I think it should run better on a laptop with a Geforce 520m graphics card, even if that GPU is fairly weak. I hope the game gets proper optimization until it is released.
Skippable story stuff?
Why can my allies skip the NPC talk for me? Makes no sense...
Randomly generated outdoor levels?
So far I did not see any randomly generated content, even the indoor levels all seemed the same. Not sure if that is gonna change, but it's gonna make the game feel repetitive sooner than later...
That's it, thank you for listening to your customers ;D