The biggest obstacle facing the AAF, as far as I can tell, is the simple fact that nobody cares about it. It's going to be like one of those primetime network shows that nobody watches. They should just call the league CSI: Football.
I'm also convinced that China is going to defeat us in WW3. What they do with American Football is anyone's guess, but below I've listed a pretty good outline of the sports that Chinese citizens are forced to participate in. Some of them are already becoming popular in the US.