Re the Red Card -
It is bizarre how there is basically no complaint from SA supporters about the card and that all the debate I have seen has come from other supporters which question the rules in this instance.
My opinion, the red card sucked, but it was the correct call and the rule is pretty much correct.
The only change I would make is to remove the reference to how the player falls and rather focus on the potential injury. I think this case actually shows that up pretty well; this is a clear red in my opinion, but (putting on my lawyery hat) I don't think you can say definitively that Smith's action caused Havilli to fall on his shouler/upper back. Looking at the video it is impossible to tell whether Havilli would have fallen the way he did if it wasn't for the second contact with Taufua.
I would rather that the red card be determined by the potential harm to the jumper (as caused by the challenge) rather than the result. Not sure how that would be worded, and I am comfortable that this instance should have been a red, just not comfortable that the rule as it is written is 100% right.