Yeah, in the Big XII you get the occasional good team, but in the Big "11" you're guarnteed a GREAT team every season. It would definately be a more exciting season to say the least.
And how many National Championships does the big 11 have in the last 20 years? The Big 12 has 3 in only 10 years of existance. Go back 20 years further, to the big 8 and Nebraska has 2 more, plus CU one. I would argue that on most occasions, the Big 12 is every bit as tough as the big 11. Right now, the Big 12 is top heavy, it will level out soon!!
It might not have as many titles, but it has so many teams with history. Sure the Big XII has OU, UT, and us, but the Big 10 has Mich, Ohio State, Penn State, and even Wisconsin in the mix, plus the Iowa game. If you could make it through that schedule, you would be guarenteed a shot at the title.
You're right eventually the Big XII will level out, but wouldn't it be great to play an Ohio State in Lincoln every now or then, or maybe every year. That would be really exciting.