Their schedules and format provide a divisional runner-up like Ohio St. and Florida St. last year or Louisville/FSU or Ohio St./Nebraska/Wisconsin or Texas A&M/Tennessee this year. Plus, the SEC and B1G have an extra path to the NY6 through the Orange Bowl contract.
In 2014, Ohio St. won the B1G and it was Michigan St. (10-2) as the second-highest ranked B1G team at #8. Alabama won the SEC and it was Mississippi St. (10-2) as the second-highest ranked SEC team at #7. Neither MSU played in their respective conference championship game.
In 2015, Michigan St. won the B1G and #7 Ohio St. (11-1) made the NY6 (in addition to #5 Iowa, the CCG loser). #1 Clemson won the ACC and it was #9 Florida St. that made the NY6, not the CCG loser North Carolina. Neither Ohio St. nor Florida St. played in their conference championship game. Plus, the SEC got #12 Ole Miss into the NY6 through the Orange Bowl contract.
The B12 will have a hard time to get a team into the CFP AND have another team finish in the top-10.
I agree about the PAC. With only 12 teams and 9 conference games, there is a lot more parity and the win-loss records and rankings reflect this. The 2015 PAC championship game was 10-2 Stanford v. 8-4 USC. The runners up were #15 Oregon (9-3) and #22 Utah (9-3). It's not a coincidence, it's schedules and format.