This is Blizzard we're talking about.
Kinda like how they could've reworked all the bone/corpse enemies in Wrath, right?
Oh wait. Changing Japanese-style architecture, lore style, cultural influences, and other concepts takes too much work compared to getting rid of the bones on the Forsaken.
When someone asks "Why don't we have Pandaren?" and they answer "China has problems with them," I'm going to take that as the answer. Even if the answer is glib and rushed, it's still the closest thing we'll get to one.
You're also not recognizing the nation of China as a concept vs. individual people IN China.
Wrath of the Lich King may not be released, but many people opt to play it on a Taiwanese server instead or get it through a completely different source. These same people can still be offended by the Pandaren. And again, you'd need to rework many more factors. Stars is a Chinese guild and they killed all content a long time ago.
http://www.gamespot.com/news/6205915.html And apparently the ban is complete crap anyway. There's issues going on with And9's distribution.