Like others have said good idea but poor implementation. If it was up to me, I'd use VAR sparsely in game changing conditions e.g goals, offsides, penalties.
Each team would have 2 or 3 VAR challenges and, similar to tennis, if they get one wrong, they're down a challenge. To prevent misuse, maybe the offending team loses 2 challenges for a frivolous appeal.
If there is very little in it, the VAR should advise the ref that it's too close to call and that the match ref should make the final decision. Similar to NFL, there must be indisputable evidence for a decision to be overturned.
As far as how long it takes to make a decision, I'm sore that can also be improved. Rugby, tennis and cricket have shown decisions can be made very quickly. Given time, football may be the same.
At the end of the day, VAR will make the game better just like goal line technology did. It just has to be used correctly.