I honestly believe that referee's love football, and have hated given some of the decisions they have because their hands are tied by the rules, if given the power and freedom to do so, he would not have disallowed that Kane goal.

Finally what is the downside of all this.. ?

well consistency...
some refs will obviously have different styles and outlooks on the game than others. BUT THIS IS OKAY.

As long as a referee is consistent within the match it does not matter if referee's are not consistent compared to each over, once again this is common and accepted in boxing / MMA . eventually each referee will have their own styles and personalities and players and managers will learn and be prepared for this.

They will still be held to standards and performances reflected on, so really bad refs will just get found out and demoted and good refs have the freedom to rise to the top.