One issue with your idea (which is quite valid, BTW), is that the "leser" conferences only get a what's left in terms of a BSC bid. Say Bozo State, Utah, and Cincinnatti all finished unbeated, and somehow ND got into whatever position they needed to so that they get their "autobid"- which I think is top 8. OTOH, go with two of the auto conferences finishing outside of the top 10- you choose two. With ALL of that jumbling, of the 3 undefeated teams, even if they were 1, 2, 3 in the country- only ONE would qualify for an at large BSC bid. If wiki is right, no more than one team from the C-USA, MAC, MW, SunBelt, and WAC can get an auto birth in a given season.
The ACC, Big 12, Big East, Big 10, Pac-10 and SEC champs are all guaranteed a BSC spot, even IF they are not in the top 10.
Just think of the pandemonium if the final standings were (and I admit, it's never, ever going to happen, but I'm biased for UoI):
1: Idaho
2: Utah
3: Cincinnati
4: Florida
5: LSU
6: VT
7: WVU
8: ND
9: USC
10: OSU
11: OSU
etc.
Of that top 3, only Idaho would qualify for a BSC game, and it would still be controversial of the top game. And lets even assume that Idaho, Utah, and UC all played tough games in OC- say a few teams from the P10, B12, and B10, so it's not like they played pansies. Still, Florida, who playes some patsy from Florida would get the a bid for the championship game, and Oklahoma State would get over Utah, and Ohio State over UC.
That's how it's about money vs. anything real. And, sadly, I become a lot less interested in watching any games where it's a patsy. I turned off the DS game, since it was so bad- those potential advertisers surely missed out there. IMHO, regular season ratings are going to start suffering as these weak teams are scheduled. I have NO idea how they could claim +100k this past weekend at the Big House- the rush to leave at half time was really funny.
Anyway, that's my rant.