Beneford can't run with the burners. So, he is limited to what he can do in McD's scheme. He may grade out well, but, man coverage is a problem for him. He was a late draft choice for a reason....lack of top end speed. Douglas is clearly on a lower plane than he was in 23, just getting older. Bills would only retain him for veteran minimum, as he is better than Ingram or Lewis. Johnson had only a fair year, but he is still solid, maybe the game breaker he was a few years ago. Yup, new talent is needed in these positions.
As for safety, Rapp and Bishop can play, just not at the level we have been used to. Bishop may yet develope into the player we need. Hamlin should not be retained, good slow soldier. But, a good tackler like him might hang on in the margins. Again, one of the top thre draft choices needs to go here.
Looks like a DE, CB and Safety round 1 and two to me. (where the Bills have three picks) Another late round db might also be picked if he has the speed necessary to cover the burners.