Just imagine a scenario where a team doesn't get awarded a goal due to incompetent refs and loses the title on the last day. The old 'decisions balance themselves out' is unfounded. It might do, it might not. It's pot luck on which ref you get, which linesmen and which side of bed they woke up on. Imagine losing a title because of that. You'd be livid. So I don't buy the nostalgic and sentimental argument of leave things alone, it makes it more exciting. Technology levels things so that it matters less which ref you get or which set of divers you play.
Technology is a good thing for football, particularly in the world of diving, feigning injury and conning the officials. It just has be added properly. Apart from goal line instant reports, it's not been done so.
Not sure I agree with others that you should just get 2 appeals. Some games you'd need none, some games against say Barca or PSG, you'd need 10 due to their constant diving. Minimum of 2, refunded for each correct appeal.
It has to be used for red/yellow card incidents. A retrospective ban isn't enough. Someone gets a yellow rather than a red, but ended up winning the game and banned for the next 3 games. Pretty sure the team who lost would be royally pissed off when they should have been 11v10.
Offside rule needs changing entirely anyway, VAR alone won't fix it. FFS, when it's being called back because a hand was infront of the play

Some realism here. I liked the whole 'clear air' rule there used to be and I also would scrap the 'not in play' or 'second phase' ****e as it can all be manipulated. Keep it simple. Makes it easy for VAR to allow/disallow goals then.
Mistaken identify, whatever, for the 1/10000 games it makes a difference in, why not.
I would let the video ref have open communication with the field ref. Talking about anything/everything that's occurring much like pundits do now. Ref should trust them as part of their team, nothing to do with giving away power. If needs be, anything contentious can be viewed by the field ref, but otherwise just listen to the VAR ref's opinion! They're just as well trained as you are.