The major issue with VAR is that the more people you have involved in decision making the less likely you are to get a unanimous outcome. Every single set of eyes see things differently. And once you involve multiple people in decisions then responsibility is deminished.
The use of VAR, in my opinion anyway, needs to be restricted to a clearly defined set of circumstances (ie penalty decisions). If we use it to review every supposed clear and obvious error during matches then we would end up with a game that takes as long as American Football.
Also, there is already a Match Review panel in place to overturn any clear and obvious errors so handing this responsibility off to the VAR will no doubt result in more incorrect decisions made by officials already under pressure to make the right decision.
The officiating is already average enough in the A-League. Adding more confusion is not the answer. More training and greater accountability for officials is.