My most hated pundit phrase:
"if there was contact he's entitled to go down"
No-one is 'entitled' to go down. Going down should never be a decision of any kind. You fall flat on your face if you're unable to stay on your feet. If you deliberately go flat on your face you're trying to influence the ref, whether there was contact or not. I know it's difficult, because you very rarely get a free kick unless you sprawl on the turf, but the fact that players spend so much of their time with their face in the mud makes a mockery of the game.
As has been said, the first step to putting this right is straight reds for diving, plus a panel studying video evidence giving lengthy bans to those who dived and were not seen by the ref. Refs then have to do their bit by giving free kicks when a player is illegally impeded - not just when he throws himself across the turf.