There are good head coaches and great head coaches.
The great ones usually also have great GM's, great support staff (offense, defense, and special team coordinators), assistants, scouts, play makers, owner's who will spend big money......
Since the HC was fired, the OC was fired, almost a third of the team was injured at any given time, AND Fewell was charged with running the gauntlet without so much as a starting QB - I think he has done very well with very little.
Go back and look at Bellycheck at Cleveland. Would you have called him a good head coach? (and please do not twist that to mean I think Fewell is the next Belichek)
Fewell has not yet had the time or tools to answer your first question. I like his energy and attitude, but that is not enough by itself.
To answer your second, standards are standards and the Bills have been sub-standard for so long it is a travesty to professional football.
Just food for thought, my fellow fan!