Says you. I very rarely see a match changing mistake; offhand, I can only think of a penalty that Rangers could have got vs Hearts for handball (by Webster IIRC); even in that case it was debatable as to whether it'd be ball-to-hand or vice versa, and Rangers didn't deserve to even draw that match anyways (they were ****e).
I think you'd see bugger all actual difference in 'good' decisions (because it's just as hard to tell in real time on TV as on the pitch), combined with the possibility - strong IMO - that constant interjection would break up the flow of the match with niggly fouls that mean nothing in the overall context of the game. So long as you have any referee, you can consider that an outside influence.
The implication here is almost of bias, which becomes even more likely - albiet in a diluted sense - the more officials you have. Because I've never seen any evidence that more eyes mean better decisions; and what happens if the sideline refs disagree?
Of course, there's the other barrier; how are you going to implement this for all teams (level playing field across all divisions). I can't see 10 or 20 cameras turning up at Cliftonhill, afterall (glorified mud pit).