it's now a single player game for nearly everyone (unless you're a higher level raider)
the vast majority of players will push a button, the game then automatically forms a group, teleports you to the dungeon/raid, which is then completed without anyone saying a word (and it is almost impossible to lose)
the other players might as well be bots
loot is now dished out individually and automatically by the game: no interaction with other players is needed
higher level raiders experience the same content, just at a higher difficulty (which does require an organised group)
Blizzard has optimised out the massively multiplayer part of the MMO, and with new "features" like PvP/mob scaling they've obsoleted the RPG elements too (leveled up? your character is now weaker!)
sadly: what's left is a skinner box collection game with many infinite grinds to force you to play by exploiting the fear of falling behind your peers