sounds like it could be worrth the debate, can't see many people going for it apart from when its a touchline conversion / really windy / no kicker on the field.

As for the interchanges before it, thats far too much American Football and would slow the came, so a bit no!

It's no more of a problem than wondering what happens if a conversion kick bounces off a crossbar or post or misses and doesn't go dead.

NCAA and highschool really. The NFL resisted the two point conversion for a long time after the other ruling bodies used it.

I suppose not, but at least in that sitiuation you just rule the ball dead after the kick. Seems a bit less annoying than a situation where the ball is in play for a theoretically indefinite amount of time. I suppose if your try just put you in front with a minute on the clock, it's a good way to run the clock down.

Or you could make it un-timed.
For a while, I have felt the clock should stop after a try is scored and not resume until the next kick off is taken, anyway.