Finished the Diablo4 campaign yesterday.
It was ok. People seem to really like the tone better, I've never been able to tell the difference. Act 1, 4 and 5 (out of 5) had some neat moments, but otherwise I felt it was monotonous "let's run after the baddie" stuff. Felt the drama between characters was mostly too forced, couldn't care about a lot of them. Inarius was good, but should have been more prelevant I feel, Lilith was too prelevant but was ok otherwise. The rest were a bore, outside of a spoilery one.
Gameplay... I'm not sure what to feel. I've been playing Barbarian, and the enemies in the game run around a LOT, so you need lots of movement skills as a melee character. And it still feels sluggish. I'd have a try some different characters and builds to give an honest opinion.