American football is pretty much all about drawing up plays and executing them to perfection at lightning speed while the opponent tries to anticipate the calls. There's a big mind game component to it because of that. But then it seems over-complex to me even if I've been familiar with it all my life. It's the main reason I don't think it can catch on much outside the US where there's such an ingrained culture. Sports like Foot, Basketball and Hockey are a lot more natural and easy to grasp, which is why they spread out more, especially Foot.
But in the end, I'm not the best person to speak about American Football with since I've grown away from it since the early 90's. It's not really a big part of our culture here. Most high schools don't have the money to have football programs and if they do it's going to be Canadian rules. Nowadays, if I watch any of it, it's going to be the Canadian game. There's less talent, but it has a more blue collar feel, the rules favor a lot more offense and there seems to be more plays being developed on the fly. But I'm moving away from that too and watching more and more MLS as my second sport after Hockey.