I'd say it's the most important sport in terms of coordinated team play and importance of a good division of labor. You need big tough guys on offense and defense (moreso than you do in hockey), players who can run, dodge people trying to tackle them, and understand where they need to be on the field for a given play. Your QB has to have an amazing arm and on the fly thinking, as well as being a good communicator between the coach and your teammates.
TDs / field goals are scored different than you probably think. Saying a TD is easy in the NFL is like saying it's easy to score a goal in football/soccer in champion's league.
I'm saying all this and I hardly even watch American football.