Make no mistake Boise State is a good team.
But, where they have the advantage is they don't have to be at their best each week and can still contend for a BCS bowl game. If you want to be in a BCS game out of the Big Ten, then you better be at or near your best every week. Mid-level Big Ten teams have enough talent to upset top level teams in that league (even moreso in SEC). Mid-level teams in the WAC have NO SHOT at beating the top teams.
I'm in the camp that thinks Boise would not win the Big Ten. They can play one or two games tough against high quality opponents with ample time to rest and get healthy as evidenced by their bowl success. But the grind of an entire Big Ten conference schedule would eventually wear them out. They don't have the depth nor the overall talent level to keep competing at a high enough level to contend for a conference title in the Big Ten or SEC. I'm not even convinced Boise would win the Mountain West with the likes of TCU, Utah, BYU, etc (we'll soon find out).
It is one thing to play Nevada, Utah State, Hawaii, Lousiana Tech, Idaho and Fresno in consecutive weeks as Boise State gets to do.
It is absolutely, positively something entirely different to play a schedule like say - Penn State, for example: @IA, Illinois, @MN, Michigan, Northwestern, @Ohio State, @Indiana, Michigan State (throw in PSU's game @Alabama and Boise State playing that schedule is more likely to be playing in the Insight Bowl in Phoenix, not the Fiesta Bowl in Phoenix).
And, don't even get started on normal schedule in the SEC. Boise would probably hover around a .500 conference record if it had to play Dan Mullen's conference schedule at Mississippi State this year: Auburn, @LSU, Georgia, @Florida, Kentucky, @Alabama, Arkansas, @Ole Miss.