not at all what the changes were brought in to do.
the changes were brought in to get on field refs to make decisions, and then have the video referee to confirm/reject that decision without using benefit of the doubt.
previously the ref just said "i dont know, you figure it out".
now the ref says "Try, double check the grounding".
the video referee looks at it and unless he is convinced that its no try he rules it a try. theres no benefit of the doubt anymore - if the on field ref says no try, and the video referee would have ruled benefit of the doubt before, he rules no try now.
so take the mccullough example:
2012:
referee: "check grounding"
video referee looks at it a million times, decides he was short.
video referee: "no try, play the ball"
2013:
referee: "try, check grounding"
video referee looks, decides he was short.
video referee: "no try, play the ball"
in this instance, the outcome is exactly the same. its only different when benefit of the doubt wouldve come into it. basically now if the video referee wouldve awarded benefit of the doubt he just goes with the on-field refs decision. he basically says "i cant rule against what you said conclusively, so what you said stands".
its not about correcting "howlers", its about correcting incorrect decisions when there is no doubt in the video referees mind that it was incorrect.
the video referee thought the referees "try" decision to mccullough was wrong so he changed it. i agree with the change.