The four-point field goal is an awful idea. In 10 years people will be losing yards on a third-and-17 play to set up their field goal for 60 yards, or just snapping it a yard further back to make it 60 yards.
Ditto on the 50-yard punt. If it's third and 17 at the opponent's 49, you may be better served in some cases just to lose two yards. But, again, in 10 years 60-yard field goals won't be that much of a challenge, so maybe that won't happen. Teams may keep two kickers if their accurate FG kicker can't make boots from 57 or further back.
One foot - too many rules already support offensive play. I love seeing how athletes keep that second foot in play. They are some of the most amazing plays in sports.
OT - I know I'm the only idiot that thinks this, but I'd just go back to 15 minutes, flip a coin and go with it. Or, force the team that tied the game the latest to have to kickoff to their opposition. This way you may promote more people going for 2 or maybe TDs over game-tying field goals, especially if it's the fourth quarter. You know, I just thought about that as I was typing this. I really like that idea.