I never complained about Panda's. I find them no more childish then I find Tauren, Gnomes or Elves.
I honestly don't really seen anything Anime overload-ish in Pandaria either.
I just hate MoP because I hate the Asian theme. I perfectly understand that some people dig it. And that is fine. But myself and many others liked WoW because it was always grounded in Western Fantasy. Orcs and Dwarfs, Hordes and Grand Alliances, Undead and Elves, Sword, steampunk and Magic, Winged Dragons, Pantheons and Old Gods.
Asian influences were there, but they were subtle and fit the grand scheme of things. Night elf architecture, Mongol horde thing of the Orcs.
For me every single Asian themed building in MoP is an epic eyesore. I fucking hate the Shrine, Panda villages, Jade temple, and that lame ass Wall. I do sort of like Shado-Pan monastery.
This is why I think that creating an entire expansion around Asian themes was an epic mistake. One zone like Timeless Isle and a starting area for the Pandaren would have been more then sufficient.
So far 5.4 is my favorite patch, because it has the least of the Asian theme stuff, and the most of the essence of WoW. Epic fantasy.