I don't think you can look at this in a vacum. It's like chanrging someone for speeding even though they were on the way to the hospital with their pregnant wife. Cant' do that. You have to look at choices.
I'd say the first two years he did very well. Considering when he inherited the team and the Bills were double-digits over the cap with only 34 players signed, he did a great job getting us out of that mess in two years. Very good. He even managed to sign Moulds, which was a major, major coup. Getting TH in the second round was wonderful. Clements in the first round was great.
Given that, I'll use your system.
QB - C+
RJ over Flutie. As much as I hate Flutie, he was better than RJ.
Getting Drew gave us instant credibility to a team that was horrible. Recognizing that last year was the time to draft a QB was very smart, given this year's QB crop in the draft and FA.
RB - B+
TH and WM, and don't forget Shelton
Henry is the definition of 2nd round value.
McGahee was a gutsy pick that is paying off. Shelton was a phenominal FA pickup, and blocked like a madman last year.
WR - B
Moulds, Reed, Aiken, Smith, Shaw, Jett, Wright, Smith and Evans.
Donahoe made a decision to keep Moulds, which paid off. Evans was quite good as a rook. Reed was good as a rook, but I don't feel he's lived up to his potential. The grade is based on Moulds and Evans.
OL - B-
MW, CV, TT, JJ, Ross Tucker, Lawrence Smith, Mike Pucillo, M. Price, Ben Sobieski and Dylan McFarland.
JJ was a great value pick. MW played very well last year despite his slow start. I like watching him nail people. I think CV is darn good. Teague is a decent center.
TE - C+
Mark Campbell, Euhus, Moore, Nuefeld
I like Campbell. He can long snap, and is versatile. Ehus and Nuefeld are both decent prospects. Moore was a good FA pickup. Campbell was worth a 4th rounder, given his production.
DL - A
Aaron Schobel, Sam Adams, Ryan Denney, Chris Kelsay, Justin Bannon Ron Edwards & Tim Anderson
Wonder why this defense has been ranked #2 in the NFL the past few years? Starts here. Good depth, good rotation, and good starters. Schobel is a great find in the 2nd round.
LB - A+
Spikes, Fletcher, Posey, Stamer, Crowell & Haggan
These guys flat out play. Truly the elite of the NFL.
DB - B
Milloy, Clements, Vincent, McGee, Thomas, Baker, Greer, Wire, PP, Raion Hill
Milloy was a great signing. Vincent's ability to play safety and CB is valuable. Wire is a good athlete, but gets paid way too much $$ and I feel he's reached his potential. Clements is obviously a great pick.
K - D
Lindell & Hollis
I really dislike Lindell. D+ is generous, IMHO.
P - A+
Moorman
ST - A+
McGee, etc.
No way you can't give this amazing group a great grade.
Overall
B+