Problem with that is games would be going on for days. Aside from offsides and ball in and out of play, almost every decision in football is subjective. If you take away clear and obvious it would at least triple the number of decisions VAR gets themselves involved with.
I'm comfortable with clear and obvious, but there will always be some inconsistencies, and that is why they need to release the audio. For today's one I'm certain Anthony Taylor gave it because he thought the attacker had been tripped by the defender's leading leg, and that was very clearly and obviously wrong as it made zero contact. If they released the comms it would just make it so much more clear to everyone and shut down a lot of the conspiracy theory nonsense.