I'm pretty sure a bunch of the D3 team worked on D2 but anyway. His biggest complaint seems to be with the story and that's not something they can fix up with patches. I mean hey, it's never been a strong point in the Diablo franchise but its new levels of unintentional camp/bad in this one. Oh and *turns lever and gets pointless 5 second event* Less is more with the story in Diablo games.
Besides, D2 and WoW grew over several years so big content patches aren't necessarily going to come fast and furious. People waited a decade for the game, no surprise some aren't happy when they feel their expectations weren't met.