Just to be clear, I am not saying I agree with it. Shane's clutter point is valid.
I think recent weeks have demonstrated a shift from all and sundry towards paying the free kick or balling it up quicker (e.g. how much prior opportunity do they get). My reading tells me the majority would like to see more frees paid and quicker in order to reduce stoppages. A ball-up creates a stoppages, a free kick creates spread - then run and carry - then kick to a player in position.
Hopefully, the fourth ump will not only find 3 extra frees per game, but will also help in determining if there will be a ball up more quickly. I.e. player gets ball, gets tackled, holds ball in, falls to ground, rolls around for awhile pretending to try to release it, umpy finally says "i'll have it" - by then every other player around the ground as come to the pack and we have mauling stoppages from then on. Not sure what the 4th umpy will do here, but hopefully player gets ball, gets tackled - umpy decides prior opporutunity yes or no - yes free kick, no ball up - straight away, dont muck about - stop the stoppages.