Genuinely curious, what would your suggestions be?
Well, making offside feet-only would be a great place to start. I think the whole body is just too much of an advantage though -- that's like five feet.
Also, make any tactical foul an automatic yellow. Over and over we see guys get beat and they just rugby tackle the offensive player. Open the game up like the NBA and Hockey have done to great effect. They've done a lot here already, but definitely could do more.
Maybe some sort of group-stage half-point bonus for 2 or 3 goals scored in a game. Make a 2-2 draw worth more than 0-0. Stuff like that.
I spent all of 30 seconds thinking about it, so these may be terrible ideas.