I've seen this proposed before, sort of like a football version of a 3 point shot.
I think it should be the other way around, there should be MORE points for a short FG, to reward you for driving deeper into enemy territory. If you only got 2 points for 50+, for instance, It would put more pressure on the offensive team that is driving for a FG at the end of the game to tie or win, they'd have to get down to the 30 or so to get 3 points.