The 1 rule I would change, and it is a really insignificant one that I think is just a coping mechanism from the Isaako days but, I think a kick off going out on the full being a standard penalty is to harsh of a punishment.
What I would suggest is that if a team kicks out on the full, the opposition gets the penalty but they should have to take the tap at half way.
Getting to kick for touch because a kick off went out on the full is such a severe penalty for a pretty minor error that occurs at the opposite side of the field. You kick out on the full, they kick for touch, and now you are defending on your own 20m line. A 50m penalty is enough without making it a 70m penalty.