I think you've misunderstood; we're trying to Americanize the game, not make it better...
See? Someone understands what I am saying.
Have teams of about 33 with the ability to swap people on and off at will, and time outs to do so. Entirely swap the team over between attach and defence.
That's how recreational leagues work in my part of the world. Unlimited substitutions during a stoppage in play.
Replace yellow/red cards with some kind of sin bin arrangement.
Like that as well. Works well in rugby.
Get rid of the goalie; he just stop points being score anyway.
Actually, I would go in the opposite direction if scoring went up. Make the goal smaller. This would make for better goalie play and more spectacular saves. The perfect "American" final score would be about 3 to 4 goals a side on average.