If there was one rule in the NFL that I could change it would have to be the timeouts. I would give teams five timeouts per half. I would do this to give players more rest during a game. It would also let coaches come up with better strategies and game-winning plays during a game.
I know as kid playing football you can get tired easily. I really learned that after I played HB, ROLB, WR, and SS, so I could imagine how the big guys get tired. I think two additional sips of Gatorade could help a lot. It would give players sometime to think about the last play and how to make the next play even better. I think more rest equals better play, especially for the veterans.
Also, I would think an extra two timeouts could be beneficial for coaches to invent a new play or a better game strategy that can help win a game. For coaches like Jim Harbaugh, a timeout can give them a chance to recover their voice. 5 timeouts can make a huge difference when there's less than 2 minutes in a close game.
So, what rule would you change?