To me, if they just review goals automatically like they have been (is it in the net/cross the line, or not) thats enough.
I really dont care if a guy is offsides and its so close you have to slow it down in replay to make sure, just play the game. The obvious missed Leon Stickle type offsides calls are pretty rare IMO..as often as they miss an offsides call (by not calling offsides) they probably miss it the other way and call offsides when it wasnt....you just deal with it and move on
game is played by humans, coached by humans, and officiated by humans. The players make mistakes, the coaches make mistakes, and so do the zebras.