How quickly people forget....
How you can think back to the New Mexico State, NDSU, South Dakota (Brewster's final year, I know), and the 2011 Michigan game, then compare to now (just four years later), and not rate this an "A" is beyond me.
Easily. The Brewster era would be rated a C- (or something like that). Brewster had two lousy seasons (1.5 actually) and two mediocre seasons. Kill had 1 lousy season (and possibly another before this one is through), one mediocre season, and two good ones. The performance of Kill's teams rate a B compared to Brewster's C- but not an A.
If you want to be sentimental and empathetic about coach Kill, that's understandable but that doesn't have to lead to grade inflation.