I have to say I love the Pandaren. The work Blizzard put into them with the art, animation, voice acting and lore make them very animated and alive. More so than the other races I believe.
Whether they belong in Warcraft, well, that's up for debate. I'm sort-of on the fence. I think they are a great race. Animated, alive, detailed. More so than you would expect for "panda-people" per say.
However I think why they can seem out of place is not because of their production values but I think because they echo an eastern/asian art style while most of Warcraft is based on traditional western fantasy. Hence the Pandaren are the exception or the break from the traditional.