I actually quite like American football, although I would say I prefer soccer.
My main issue with American football, is how stop-start the game is. It's a few seconds burst of play, and then immediately snapping out of character, and ambling around for a bit until play resumes. With such stopping and starting, there is little fluidity to the game and thus I can find it hard to get into if its not an engaging match. Then there are the advertisement breaks (which I am convinced are the reason behind each break in play taking so long), these contribute to stop-start feeling of the game and break the excitement and tension up too much for me.
While it is is a 90 minute game just like soccer, these breaks in play can make matches last two or three hours, which means half of the time I'm watching nothing happen. Sure tactics, and plays are discussed but it really starts to drag on - and then I am hit with another advert.
The best thing about American football for me (apart from the tackles) is how territorial it is, grinding yards out and gaining land. It reminds me of 'capture the flag' style games I used to play on video games. The closer you get to the scoring, the more the opponents start to dig in and try and push you back, and you need to use you're head to gain that final bit of distance required to win.
I can understand why people don't soccer, if both teams adopt defensive strategies, the ball just goes back and forward in the midfield without ever really threatening either goal, its likely that both teams will go a full 90 minutes without even scoring and it can make for very tedious viewing. What I enjoy about soccer from a viewing perspective, is that while goal tally's are often low, a goal can materialise out of seemingly nowhere and this can completely change the game. A team can be on top and dominating but at only 1-0 up, the other team can easily score an equaliser in a moment, despite being against the run of play. This adds the unpredictability to a game, and its the sort of thing you don't tend to see in games like basketball which you highlighted. Since basketball is such a high scoring game, how well you're team is playing is almost defined by the scoreline, this is less likely to be the case in low scoring games such as soccer. While this is obviously most rewarding to the better team, it takes a certain amount of unpredictability out of the game, which is why I don't find basketball too interesting to watch.
I don't get to see all that much American football, but the stuff I do get to watch is all at the top level. It's obviously a game that is great from a commercial perspective, all the breaks in in play are a great time for an advert. In fact, part of me gets the feeling, that the long breaks in play are intentionally there to boost advertising revenue and bring more money to the game, or then again, perhaps its just me being a cynical person. If it is the case however, I can't really blame the organizing body for making that decision. If that is the case though, I suspect I would derive more enjoyment from an amateur event, which would surely be less commercially driven and hopefully as a result, a bit less stop start.