WoW has been progressively less immersive as time has gone on. Particularly on the Alliance side after Cataclysm. I feel this is largely because jokes becoming about gags and jokes rather than the story. It completely breaks the immersion of the game when I'm suddenly confontred by WoW's Rambo, CSI Westfall or Harrison Jones.
The odd reference or gag is fine. But there are far far too many at this point.