I have a different opinion on Rakete-Stones yellow card.
The rules have made it such that - as long as there is head contact, it's serious, hence a whole series of red and yellow cards.
Also, everyone wants consistency - and the easiest consistency is - if there is head contact, you're carded. If the guy is going down, maybe you escape with a yellow.
But this is a self-imposed trap. We've all played the game. Your head, especially when you carry into the tackle, is not very far from your shoulder and chest. When someone hits you in the chest or shoulder, some part of his arm or shoulder is going to hit your head. In the case of Paisami, I don't believe he was falling down. But I do believe the vast majority of the impact is on his chest and shoulder, and while the top of Stones' shoulder touches Paisami's head, it was incidental. Paisami's head barely even moved.
Just like the Drua's hit on the Blues reserve hooker - which is right on the head - the hooker was what, 70-80cm off the ground? What do you expect the defenders to do?
THere's a second part to the equation - is it really realistic that there is absolutely no head contact whatsoever, when at least (very conservatively) 50% of all runs, the attacker dips his head slightly into contact.
Unfortunately, the nature of rugby will always carry a risk. If you want to eliminate too much risk, the change might itself be excessive,
ALso, I do believe each individual contact warrants a little bit of adjudicating. Each situation is not the same.