1. Get rid of the offside rule. Linesmen always get it wrong multiple times per game, taking away legitimate scoring chances in an already low scoring game.
2. A real game clock that is visible to everyone in the stadium, that stops when the ball goes out of bounds or when the ref blows the whistle. Corruption charges have already rocked the game, yet they continue to allow refs to hide the time, then magically add on one minute of stoppage time when the favored teams best player has been rolling around on the ground like he was shot for five minutes, never mind all the other stoppages in play.
3. Which brings me to my next point: If a player goes down with injury, he has to come out of the game, at least for a certain period of time (say 5 minutes on the game clock). If he's really injured, make sure he's okay before he goes back on the field. But more importantly, maybe the primadonna fakers will think twice about acting up too much if it means they have to come out of the game.
4. Unlimited subs. I know that this might be a sticking point for players that want to prove they're somehow more fit than players of other sports, or managers that want to prove they can make strategic substitutions. But the fact is, you get lots of players that coast for too long to pace themselves for the whole slow-paced game instead of playing all out for as long as they can, taking a break, and going all out again. You get players that have to stay on with injuries because the team has run out of subs. Or, as mentioned above, you get the players rolling around and faking injuries so they and everyone else on the team can catch their breath while the clock runs down.
5. Lose the shootout. Sure, it's exciting, but it's not soccer, and it's not a way to decide who a world champion should be. But obviously, you can't have games go on forever. How about this: in overtime, every five minutes, each team has to take a player off the field. By half an hour into overtime, teams will be down to five-on-five, by which time there should be lots of open field to come up with scoring chances to finish the game. Here's where strategy could really come in...if you get down to a couple players, do you keep your goalie on the save shots, or keep a forward on to take them?