Here are the things i would change.
Yellow card = 2 minute Power Play
If you 'flop' you need to be subbed out for 45 minutes. If you are in SO much pain.. clearly you need to sit out for a bit. (the only exception being head to head collisions)
Offsides needs to be changed to gaining zones vs not being allowed to be behind people. Do it like hockey... For instance... trying to cause an off sides in front in the net on a corner kick should not be possible. Maybe make it so you need possession or to touch the ball before stepping foot in the goalie box. But that's all.