As I sort of said in the other thread lots of other sports only use them for objective decisions.And all of this stuff would need putting into place before it was put out into the wild.
The 30 second thing is just an example of how it could work. But I honestly don't see how it would be that difficult to do.
VAR currently is not fit for purpose. Anything has to be better than what we currently have. In theory VAR is a simple idea. A simple idea that they have managed to make a complete and utter mess of.
Other sports have a challenge system, I don't see why it wouldn't work for football. The idea of football is a quick flowing game doesn't really wash, as VAR has put a stop to that already
Tennis - in / out
Cricket - in / out
Rugby - tackle height, double movement, pass direction (not sure what else but from what I see, very little, it's objective questions).
I don't watch any American sports so I don't know how much subjectivity there is in the decisions they are taking, what I do get the impression is that no other sport where 1 decision can produce such wildly different opinions on the outcome.
It happens among referees. You seen it at training events. Same clip and you can get several different outcomes around the room.
That never changes whatever system of video review is employed.