Mushu is still based off of wushu, it still teaches how to move and how to hit, then if they want to they can go into wushu and know how to move in the gravity.
The only thing negative that can come of it is that they don't play wushu the way that YOU want them to. But that's the entire point of this game, is to have different playstyles, everyone can choose how they want to play. If you don't see eye to eye with someone, that's your problem.
Nuff said