Hmm, it seems that either YCF was a complete phony or he was really good. The entire family agreed that his choreography of the form became the standard. People can say it's because it took out the jumps and kicks, but only a few styles have forms that keep them anyway. And, it doesn't make his form easy to do.
If he faked it, he was able to have the highest salary of any instructor at the Nanking Academy. It would also mean that he fooled WCC, Sun Lutang, Li Jinglin, et al. To me, that's unlikely.
So, imo, whether he started young or only studied a few years, he had to be very very good. It's arguable that his size had something to do with it, but I'd argue that would make it even more important for him to be skillful. Plus, there must have been some formidable Yang family members still around. Why choose YCF to represent at all?
It's possible to make YCF's style difficult, and just as possible to make the others easier and more accessible.
"A man is rich when he has time and freewill. How he chooses to invest both will determine the return on his investment."