I don't have a problem with Miller not being ranked number 1. He missed games, he was great behind the LOS which got him noticed. All his big plays were sacks, or slicing in and making a nice run stop behind the LOS.
He still has to get better at his angles in the run game when he can't just blow the play up. Sometimes you have to pursue through traffic and make a play, or guard a TE or RB, those things he still can improve on. Then if he does, and still gets sacks, we can say he is one of the best in the NFL.
The good news is pressure on the QB is the most important thing. So if you are going to be a one trick pony, that is a good pony to ride.