I posted this in the fire Rex thread, but think it's applicable here as well-
It is very possible that Rex does not have the horses he needs to field an effective D.
I'm sure most of us remember watching the exotic and aggressive schemes he put forth with the Jets. Why does our D not look like that? Quite simply, personnel.
I see two main problems with our personnel that, IMO, is not allowing Rex and company to run their D.
1. Safety play. Complete garbage at safety is forcing Rex to rush three and protect the back end.
2. I don't think our defenders, at the key positions of LB and S, are smart enough to run the scheme. Missed assignments and confusion has forced Rex to be much less complex than we have seen when he has fielded strong D's. Maybe Ragland is the answer at LB and hopefully we can get one of the stud safeties in the draft.
I am still a fan of the Ryan defense, I just don't think we've seen it on the Bills yet. It is more dependent on specific personnel than some schemes (Schwartz), but, when you DO have the players- it's a joy to watch.
I think it is possible that Ryan and Whaley don't mix well in this regard. Whaley seems to like certain body types and physical attributes, while the mental side is more important to Ryan.