Then how would you know if it's reviewable prior to reviewing it? If you aren't sure where it crossed, then how do you know if it crossed completely inside, outside, or partially? And I agree with newtogolf's post up above: It's not at all reviewable if the ball is higher than the posts. At least, that is what the announcers said after the game.
Again, based on the info relayed to us by NBC after the game, this is wrong as well. They said that if any part of the ball is over the upright, then it is good. So like I said above, a ball that, were it 5 feet lower, would just kiss the outside of the upright is considered good if going over the top of the uprights.
There is an easy solution to this one: Make the uprights higher. I would think that 30-ish yard field goal would be the one where the ball is at it's apex nearest the goalposts, and you rarely see them kick balls higher than the posts, but when you do, its only by 5-6 feet at most, so make the posts 10 feet higher. Or strap on some "Hawk eye" technology like they have in tennis and be done with it. Now you don't even need to have the refs stand under there.
Should it have been reviewed... maybe but I'm not sure it would have changed the call because every replay I got to see the kick looked good. (note: I'm not a Ravens fan)