Fell flat the next? He had his best year last year. He didn't allow a single TD in coverage, and as QB's shied away from him (only 21 targets), he still managed to pick off 5 balls and change the outcome of at least 1 game (maybe 2). He's the best coverage free safety in the league, and aside from an aging Ed Reed the best free safety in the league period. If you indeed watched his play last year and considered it average, you either a) don't know the difference between a strong safety and a free safety, or b) need to cut back on your liquor intake during these games. There wasn't a better free safety on the field last year, and I'm not just saying that as some blindly-devoted Bills' homer.
If you want to make the argument that a safety isn't worth $8M+, okay, that discussion has legs. But to say he's average and can be upgraded is laughable.