I disagree on principle anyway because I don't see why the defending team should get a free 22 metres upfield - much like why we don't allow advantage after a knock on into goal to result in a 22m DO if forced by the defending team. Possibly you could be on stronger ground to say the defensive team should get the put-in to the 5m scrum, but I don't really don't see why it should be changed.
However, even saying that, I think you are missing a crucial part of this law, that is perhaps more relevant for the 99.9% of games with no TMO, than for the ones on TV. Very often when the attacking team gets the ball over the line, they have in fact scored, but if the referee can't see it then he can't award it. The fairest thing to do is to give the attacking team the ball back. After all, they may actually have just been robbed of a try.