A 1 camera set up would mean there will be no changing of camera angle mid-play, usually just as a player is running down the side line close to the try line. That really annoys me.
Save the fancy editing for the replay.
I think it was the NZ v SA game last year where they changed to the side line camera just as some was about to score, but all we could see was the back of the touch judge.
Slightly off topic I know...