This is one reason why it's a no from me, as well as others that have been mentioned.
I think (harsher) retrospective punishment using video evidence could be a good thing though. Although then take a situation like last night, in which Henry apparently told the referee that he'd handballed it but the ref still stuck with his decision. Do you then dish out a ban to Henry? Yes he could have put it out after the handball, but I don't think it would be the natural reaction of a player (and Doyle pretty much said so himself, saying an Irish player would/could have done the same) to do that.