Firstly we resign Bob Saunders last season's DL coach who has previously worked almost exclusively with 4-3 lines and left the Packers because they moved to the 3-4
Secondly, Giff Smith has been recruited as a defensive assistant. No mention at all of the term outside linebacker coach.
Might it be that both Gailey and Nix have realised that there would be more of an upheval than initially thought in shifting to a 3-4 defence and that it seems that this defence is once again seemingly losing popularity with the overall success of 4-3 defensive teams getting to the SuperBowl.
It would not surprise me that the DC might be happy running either formation which I think would be the best outcome for the Bills.