I am thinking for us "rational fans" (if you excuse the oxymoron) a good season is one where our team did better than we expected preseason (and hopefully beat our main rivals). A poor season, well, ...
I tend to be a bit negative preseason, seeing flaws and issues, this year I was too positive dismissing the flaws and thinking our OL would be professional grade. (I still don't understand why they were not.) Returning very good QB and RB stable, check, returning defense, check, good special teams, questions at wide receiver, but meh, RTDB.
So, we beat our rivals, check, lost one game inexplicably, and got blown out in the CG, still for some reason ranked 5th, made in NY6 bowl game, yay. Upon reflection, not bad of course, but still disappointing.
Teams like Baylor and Minnesota had fantastic seasons, and Iowa did well, Utah and Oregon did well, Virginia and UNC did sort of well relatively, LSU did well I think, Michigan is probably on the other side among the majors along with Texas. OU did about as expected with some close calls. USCw saved their season a bit there. Rutger and Arkansas, holy cow.
UNC will be interesting next year I think, not that they will be 10-2 or anything.