Basketball and Football: Coaches shouldn't be able to call timeouts. I don't think they should have any official part in the game, because they are not actually playing the game.
1) Eliminate the illegal motion rules, who cares.
2) Eliminate the 6 men on the line of scrimmage rule.
3) Put a bar across the top of the goal posts to force kickers to kick it lower, making closer field goals a riskier choice.
4) Eliminate the eligibility rules for catching passes. If a Left guard can catch it, let him.
1) Eliminate the slide under move to take a charge.
2) Eliminate goal tending after the ball hits the rim (which I think the NBA is going to do)
3) Widen the floor to eliminate the close corner three and give teams more room to operate.
4) College needs to shorten the shot clock to prevent the Wisconsin offense.
5) Eliminate the music during play. During time outs is fine, but not during the game. It tells the crowd, "we don't actually need you to pay attention or be interested, we can make our own noise,". OR go whole hog. Run the NBA like and And1 tournament with a DJ spinning tunes for the entire game. I played in a student-staff basketball game and we had the local hip hop station DJ the game. The in game music was tremendous and the energy from it was non stop.
I'll leave out baseball for the actual baseball fora.