Very few goals could ever be celebrated instinctively then, as they would probably be subject to a speculative challenge, 'just in case'. Unless the number of challenges was capped at 1, which would be fine. Use it at your peril.
I'd rather see VAR running throughout the game as the referee referees the game and intervenes without reference by informing the referee of the decision to be made ONLY when there is a clear and obvious material error. So if marginal offsides are missed...tough shit. Obvious dives (like Sterling's) and two yard offsides (like Aguero's) would still be picked up. No stupid screens for the refs neither. Either the referee is right or he or she has made a clear and obvious error in which case he or she is simply corrected by VAR and changes the decision immediately.
