I was listening to San Diego Sports radio last night. They were actually very classy about the whole thing. They said that if baseball had the same standard or review as the NFL, the call could not be overturned because the runner's hand was obstructed by flying dust for a short time and there was no way to know if he ever snuck his hand on the plate. No conclusive video evidence.
I have another test. Look at the plate after the play. It is pristine. No dirt on it what-so-ever. How many times have you seen someone slide into the plate? Have you ever not seen an umpire have to dust off the plate after the play? Obviously Holliday did not touch the plate or there would have been some dirt left behind on the plate. If the dirt didn't get past Barrett's block of the plate, there was no way a hand would.
That being said. I am against instant replay. The right team won because the non-HR would have ended the game in the ninth. Karma.