For what it’s worth. I also think just important situations would have to be decided by video help. Except that scored goals aren’t the only important situations. There are also the cases when the ref stops play because of a wrong off-side, and the play might have resulted in a goal.
To fix this, I would think the way to go is to change the off-side rule, such that there isn’t an off-side in the first place unless the action results in a goal. This way, only scored goals would have to be checked via video evidence, and this *could* be done without disrupting the game flow. It would even improve the flow, since the majority of present off-sides (right or wrong) wouldn’t be called any more.

Of course, video evidence shouldn’t be limited to this. Every important incident should be checked. I believe it could be done with none or minimal game flow interruption. I’ve written on my site how I think it could work.

Video replays for offside decisions aren’t useful tools at all though. First of all: you would need to play out every potential offside situation to see whether it results in a goal or not, and then you need to decide whether it was offside or not. And this would seriously disrupt the flow of the game. You can’t just recheck goals that get scored and ignore every other offside call. Plus: cameras distort the perspective and can give a wrong impression of whether a player was offside or not. I’ve seen 3D reconstructions of offside calls, which looked wrong from the camera’s perspective but spot on in the reconstructed version. So, you would need to implement a more complex technology to deal with offside calls. Until someone comes up with such a solution, we’ll have to live with outrageously wrong offside calls. In fact we’ll have to live with them even longer, because FIFA will probably need another 20 years before they allow a proven technology to be used.