Note on American sports in Spain: Basketball is very popular. The Spanish league is one of the two or three best in Europe, and many former NBA players play over here. The Catalans are very proud of their homeboy Pau Gasol, who plays for Memphis in the NBA. The Spaniards just don't get the concept of baseball, perhaps justifiably. As for American football, the Barcelona Dragons of NFL Europe are not precisely a hot ticket. A common Spanish complaint is that it's exciting when there's a nice pass or a good tackle or a long runback, but the game is just too slow and has too many interruptions.
What I'd do to get rid of all the damn interruptions is to set up a very simple rule: Allow no substitutions during a series of downs and allow only thirty seconds between plays. Substitutions during a series could only be made if a player was injured, and that player couldn't return to the game. This would reduce the time between plays and would force the team to always have a player who could kick on the field, since you wouldn't be allowed to bring in specialist kickers and punters. The all-around player would have a big advantage over the specialist; you'd want decathletes instead of sprinters and weightlifters. You wouldn't see nickel backs or designated pass-rushers or third-down backs or deep snappers or quarterbacks who can't do anything but throw. Teams would go for it more often on fourth down and a 40-yarder would become a long field goal again. If you proceeded to get rid of TV timeouts, allow the same 30 seconds for a change of possession as for any other break between plays, get rid of the two-minute warning, get rid of video replays, and cut rosters to 40 players to force everyone on the team to be able to play both ways and in several positions, that should bring the game down to a little over two hours and make it a lot more exciting, much more like the glory days of the late fifties and early sixties that old-time fans remember as the best years of the NFL. As for TV commercials, there would be a lot fewer, sure; that would make them more valuable so the networks could charge more for each one--and if the game became even more popular because it was faster and more exciting, the ad spaces would cost advertisers that much more. Will they do this? Naah.