Putting aside the teams involved, which any analysis of the rights and wrongs of VAR has to do at this stage, then it is increasingly clear that the issue is not with the technology, it is with the rules, their specifications and their interpretations. Left to the officials they can (more often than not) make a considered judgement about the "spirit" of each law in each case, whereas technology slaps a black and white judgement on the screen and it is a brave official that overrides it.
What I mean by the 'spirit' is the principle behind the law, rather than the exact mechanics of how it is written - So for instance, the element of intent against unavoidable in terms of handball, and for offside the attacking player actually being in front of the defender in any meaningful way, rather than by the width of bootlace. Similar judgements need to be made in terms of contact/pushing/holding etc where too much emphasis on the black and white will mean football becomes a fully non-contact sport.
Personally, for offside, I feel that how it should be set up should mean that the players (and officials) should be able to judge themselves whether they are offside or not, which has always been the case up until now. But once you introduce precision measurements, then an attacker cannot be certain of being onside when 'level' with the defender without taking a half step backwards to be sure, which goes against the principle of the benefit of the doubt being with the attacker. I would suggest that a buffer zone of say 6 or 12 inches is used and the attacker is only offside if they are further forward than that at the crucial moment.
For the other more subjective issues, then I think most of the time we know what we do and dont want to be given, but struggle to write a set of simple but clear regulations to legislate for that. Without VAR the officials can use their own judgement on these issues, but with it, there is the danger that they will be forced to give decisions that they dont want to be giving, and go against the spirit of the law, because there are a million TV screens around the world demanding that they follow the letter of the law.
Eventually, the principle of VAR will be a benefit to the game, I just worry that not enough thought is going to go into how it is to be used for the games' best interests.