PlayStation

I played it on PC, the game is very grindy and still very unbalanced. The biggest problem is the scaling, you never feel like you get powerful because the enemies get just as strong as well, so it just feels like grind for the sake of grind.

The cooldowns on skills/spells are annoying and hampers gameplay, especially if you're playing as a Sorc which is badly nerfed. Also, the lack of a mana potion mechanic means you can't spam spells, so you have to keep switching back to your basic spell - which is rubbish.

The loot isn't really memorable and even "legendary" items feel like junk and don't have the same sort of oomph like the loot in D2.

The monsters are dumb and unimaginative, with stupid names like "horror", "arsonist" or "beast" - which is just a frikking bear. They don't even make any cool/cute grunts or noises, it's like they're lifeless. Like the Fallen, not only do they look weird in D4 for some reason, they no longer shout "Rakanishu!" or "Colenzooo!". It's like they just made some random trash mob for some generic ARPG - there's nothing Diablo-y about them. Actually, the same could be said about the whole game, it just feels soulless. No memorable NPCs either with iconic dialog (remember Cain's "Stay awhile and listen"? you won't see any such NPCs here).

TL;DR if you liked the Diablo series because it was Diablo and not just because it was an ARPG, then you'll hate D4. But if you like Diablo because it's an ARPG and you like ARPGs and blind button mashing and don't really care about the atmosphere, details, story, gameplay, loot etc, then you may enjoy D4.