Should have had it in from the start - tennis, rugby, cricket (apparently) have all perfected it. Should have the interaction between the ref and VAR broadcast too so everyone knows what the decision was and more importantly how they reached it.
I think offsides should be exempt from challenges - they're moving to a semi automated system which works fine in the CL... if the ref and linesmen let it do its job rather than blowing up early.
It depends what you mean by 'perfected' it in Cricket?
I've seen / heard a lot of complaints about VAR that same incidents can reach different conclusions depending on the original onfield decision - so if the ref initially gave a soft pen, VAR won't see enough to overturn; But if another doesn't give similar, VAR again won't see enough to suggest a penalty, etc.
Well, that's pretty much exactly how Cricket works. If the umpire gave it out, and the ball is shown to be just clipping the wicket, then it stays as out. If the umpire gave it not out, and its again shown to be just clipping the wicket, then it stays with umpires call as not out. So the same situation can be out or not out depending on the onfield decision. Just like the penalty inconsistencies that get people annoyed in Football.
Cricket for many years of technology also spent absolutely ages analysing close ups of bats or feet to see if parts were grounded just on or just behind the line when looking at potential run outs or stumpings. These were often subjective in the end, as it was such fine margins. The same with whether a catch was cleanly caught or whether the ball touched the ground at some point. These would go on for ages and would never be 100% proven either way, just ended with a subjective call from the officials.
Cricket also has plenty of situations where we can all see that a mistake was made - the player was
wrongly given out or not out - but because he or the fielding team don't appeal it then the wrong decision isn't corrected by technology. That's accepted in Cricket, and just seen as the players mistake for not using an appeal. In Football, I am 100% sure there'll be many, many instances where the media / social media go absolutely mad because a mistake was made, everyone can see it, the technology is there to correct it - 'so why are we just letting the mistake stand!? What a BS system!'
So there's 'flaws' / things to find fault with in Cricket. It's just that an acceptable level of accuarcy is accepted, without a demand for 100% consistency and accuracy otherwise all hell breaks loose. Football is different. It's so tribal, and gets so much media coverage, that every 'potential controversy' is sought out and highlighted.