The most underappreciated player on the team is, by definition, always WTE. Steve Irwin, or whatever our punter is called, would be #2.
After that, I'd probably list Gaines and even Rapp.
Browning isn't maybe quite as bad as some of his harshest critics like to say, but he is just a game manager who thinks he is a game changer. He does do a pretty solid job getting the ball to guys that are wide fucking open, so long as he can determine that they will be pre-snap and they aren't more than 30 yards from him.