Actually I think I will change my vote from Ma Long to Xu Xin. I don't even know if they will choose him to represent China, since they now only allow two players from each country, but when I really consider it, Chinese training has really reached a level where they have perfected it down to a science. Everyone on the team trains insanely hard, and receives the same top notch training, so ultimately what will make the difference is not really the training, but things you can't really change, and in this regard I am talking about different advantages in a player's body.
When you look at the last generation of Chinese top players, WLQ stood out head and shoulders above the rest of the team, even though the rest of the team still were able to overwhelmingly beat non-Chinese players. I mean Ma Lin, and Wang Hao were all incredibly well trained, what made the difference I think and what allowed WLQ to beat even those two, was the fact that body-wise he just had a combination of reach and speed that you don't see often. I mean look at Samsonov, he has the same reach as WLQ, but he looks like a turtle in comparison. His arm speed, his footwork, all his movements just are so much slower in comparison with WLQ. And then those who are actually faster than WLQ in reaction rate, don't have the height, so they don't have as good of an angle for shots as he does, and they don't have his reach.
Xu Xin is the only one I see of any player atm who has the same kind of advantages. His height and speed are amazing. The angle he gets on his forehand shots are so insane because he has the advantage of being taller, and having good footwork, and playing penhold. I think ultimately the ceiling for Xu Xin is higher than Ma Long's, and therefore if he is able to reach that ceiling, he will be even more unstoppable. And since he plays penhold, his short game will be better than Ma Long's, which is crucial since it means he will usually be able to attack first. And once he does, his shots are too spiny and too powerful to get back on a consistent basis.