Bayern manager Louis Van Gaal would:
1. Position the lineman differently, on the corner flag so they can see when the ball is kicked without moving their heads.
2. Alternately, 2 referees on the field and one watching electronically.
3. Throw-ins should become kick-ins.
4. Instead of 90 running minutes, it would be 70 minutes of ball-in-play.
5. Mandated artificial turf so that all surfaces are consistent.
6. Instead of penalty-kick shootouts, take one man off the pitch every 5 minutes until it is 6 v 6.
7. Goal-line technology to see whether the ball crossed.
I applaud his thinking. There's the problem however, that if adopted you are essentially creating rules for the elite matches that don't match the rules for second division matches and all amateur matchecs.
Number 3: Making throw-ins kick-ins is interesting, but radically changes the game. Instead of kicking the ball out of bounds for a throw in, defenses will now have a much stronger incentive to keep the ball in play. That means that long-balls will be played more, which will spread out the field. That may actually increase scoring, not sure. But it would be a different game. Funny how such a small change would have such a large effect.
Number 2: I think having referees watch electronically is crucial, especially in the World Cup (maybe in Champions League too). The last World Cup had some hideous hideous reffing, especially that Russian guy's Hindenberg-like performance in Holland v. Portugal.
Number 4: Eh. I don't mind this, and it wouldn't be as bad as basketball's end of game problems. Still, it doesn't seem necessary, though it would take remove some of the arbitrariness of the game from being dependent on the referee.
Number 5: This just isn't going to happen. I know it is frustrating when you are the better team to get your skill edge removed because the playing surface is poor, but this seems like an over-reaction.
Number 6: I think this is a good idea, although it would change the game a little bit, in that endurance would now be more prized in tournaments where this might be used. Still, it would do away with penalty kicks, which is a change any real football fan should be happy with.
Number 7: Goal line technology is too expensive. Outside of the World Cup, where it might make sense (though I'd rather just use video replay), it isn't worth it.