I play in France and my latency is usually 2 000 or 1 000 for the good days ^^ but the problem isn't the latency, the problem the LAG. I mean when your character just freez and nothing moves for a few seconds or more...
I think there's two main things causing this:
1. China is very far and you have to go through many many many many ... routers (which are maybe not really fast or very new) or interconnected network equipements to get to wowchina servers and sometimes like you can see on your tracert the paquet that you send can't reach it's destination because of multiples reasons (TTL, Routing protocol problem, link down...). So sometimes your computer waits for a long time for the responses from the server because of multiples reasons which are very difficult to explain because depending on your ISP, line, DSLAM and some other things....
2. I am not sure about that one but EVERY communication which goes from inside China to outside China especially electronical data are watched and filtred by the Chinese governement. That would explain why you can't for example go on some website from inside china like some blog website or other sites like that... So it takes some time to analyze every data and that times slow down a lot more your connections to the wow servers and any other servers in China..You can see for example that when you try to access chinese website it's really slow....
And also one last thing, some months ago a backbone cable which was handling a lot of communications towards China was broken by some boat which sank into the sea....I am not sure of that one either but since that accident my ping was awwwwwfulll and it's now almost impossible for me to play....
I thing all of this should explain our problems to connect to chinese wow servers and our ENORMOUS latency....