The penalty is an awkward punishment though.
Basically, the rule is that any foul committed on a player inside the box is a direct free kick, thus a penalty. Only things like the keeper picking up the ball with his hands if passed to by his own defense are indirect free kicks.
Currently, there is no grey area, it's either a penalty or no foul at all. This causes defenders to take risks knowing that refs often won't punish severely by giving a penalty kick for light fouls. I think the refs should be able to give indirect free kicks inside the box for light fouls (based on their own judgement). Sure, this doesn't really solve the issue, but makes it more complex. Now the refs have to judge whether something is no foul, a light foul or a penalty. I still think it's better than the way it is now though.
Also, I have no idea why there are no video refs in football. Well, I know why there aren't (Blatter and his men in their ivory tower), but there should be! Just give each captain 3 moments they can look back (like a supposed penalty that wasn't given) per half or something. There is way too much at stake to let human error be a deciding factor. Football is just so far behind something like field hockey where they keep innovating their sport.