Say you are Bob Stoops and the Texas Tech game is going beautifully for you. It's halftime and you're up 42-7, playing to create a three-way tie in your division.
Now, if you have the SEC tiebreaker, thoughts start to creep in your head like we are winning by too much. So. now it is half-time and you have to explain to your team if you beat this team by too much you will knock them, and you, out of contention.
In order to keep your shot at the conference title, you have to tell your team, well we need to let them score, we cannot beat them by too much, we need a good 3-to-10-point victory. Nothing more, nothing less.
The SEC tiebreaker actually would have made that situation plausible. Not that I am suggesting OU would have actually done it, but say they did—would you really want to let the Tech offense get rolling, and hope your defense could start playing again at the end of the game to shut them down?
These are things a team should not have to think about during a game, but the SEC tiebreaker would have penalized the Sooners for winning the game handily and would have given them incentive to let Tech score in the second half to keep the game close.
When there is a three-way tie, I think the best way to settle it is point differential against one another; not against common opponents, not against the division, or the entire schedule, because that would promote running the score up against lesser teams.
Just against the three teams involved in the tie, and yes, this does promote running the score up but against a team tied for your division, you shouldn't be able to do so. If you can, more power to you.
The only problem I see is it could penalize a team which wins with defensive battles, but that doesn't seem to be a big problem in the Big 12 (yards per completion).