competitively, I think the two are much closer to the BIG than the BIG is to the SEC. Oregon won in Columbus. TCU beat Michigan. WSU at Wisconsin, etc.
I think the Big 12 is so much deeper but the top teams in the Pac 12 and the Big 12 will battle out for that 3rd and 4th bye spot.
Creates a dynamic where they might actually for each other as long as the balance remains.