For the last several years, there has been a set pecking order in the Mountain West Conference.
BYU, Utah, and TCU were the Big Three
Air Force was No. 4, always trying to get to the top.
The remaining five teams would occasionally have good seasons (CSU in 2008, Wyoming in 2009, New Mexico prior to 2008) and seemingly turn the corner into becoming good programs. But then they would always fall back away, demonstrating most profoundly by CSU in 2009, which started 3-0 and was just outside the top 25 when the Rams went and lost their next nine games, including all eight conference games.
Things were going to chance in the MWC with Boise coming into the conference, but with Utah and BYU also leaving and Fresno and Nevada coming in 2012 (as well as a good chance that TCU departs for the Big East), the MWC will be very, very different in 2012 than 2009.
Now, different can mean good, but potentially losing the Big Three, and replacing them with the WAC's Big Three makes for a very different conference.
Even without these conference moves, the MWC was changing this season. BYU was in a rebuilding year, Wyoming had a difficult out-of-conference slate, and second year Aztec coach Brady Hoke was making real changes in San Diego.
And while BYU has recovered from its early season struggles, winning five of six with at least one more sure win coming up, the story of the year has to be the rise of the Aztecs.
SDSU looks like it is claiming a spot in the new top tier of the conference and may have done so without the departure of BYU and Utah.