The problem with that is a lot of decisions will still be incorrect and plenty of people, having seen tons of replays, will say it was clear and obvious to them immediately.I don't think the solution is that complicated, if the decision can't be met within one look at the replay then its not "clear & obvious" so stands.
Same for offsides, no drawing lines required, just look at the side view camera & make an instant decision.
If wenger did that utterly ridiculous amendment to the offside rule it would massively change the game, not to mention make it almost impossible to enforce that same rule properly at lower levels of the game without var.