While this is somewhat big news, I don't think the news is as big as some would lead you to believe. The Big 12-SEC Bowl may never even see the actual champions of each conference in asingle season. A lot of it will depend on how the new playoff is structured. Really there are only two options:
(1) A true 4 team playoff, in which case the 4 qualifying teams are removed from the Bowl process. In this scenario, if either the SEC or Big 12 champ is in the top 4, they don't play in this bowl. Most years, both conference champs would be Top 4 and not make this new Bowl. I would think nearly all years at least one champ would not make it. This Bowl then becomes more like the Capital One Bowl, which had previously matched the SEC's and Big 10's top non-BCS schools. A good Bowl, but not a game changer.
(2) A Bowls, +1 scenario. Bowls revery back to pre-BCS, pre-Bowl Alliance days. Conference tie-ins rule who goes where. The Bowls get played and then a championship game is played by the two top remaining teams. Some people believe the Big Conferences favor this method since it wouold turn the Rose Bowl and this new Bowl into de facto conference championships. The problem?
It stinks as a plan. Really does not change the existing system much. Still does not really "settle it on the field" and cuts off access to most everyone else, including Notre Dame. For those that are old enough to remeber the pre-Bowl Alliance days, many Bowl match-ups stunk. And you don't need to look further then last season to see the potential problems with this format.
Had this system been in place last year, the Rose Bowl would have been Oregon v. Wisconsin (same as it was and niether team in the top 4). This new bowl would have been LSU v. Oklahoma State (both top 4 teams). The latter bowl is a good match-up, but the Rose would be irrelvant for championship urposes. And Alabama? As the SEC #2, it likely would have pulled a Big 10 team (the SEC and Big 10 currently match their top non BCS teams in a Bowl). Maybe Michigan?
Under this hypthetical, what if OSU won and Alabama won? Who plays in the championship? OSU has to go, right? But does Alabama or LSU go as the other team? Comparable records, but LSU has every advantage - they beat Alabama @ Alabama, won the conference both are members of, and had a stronger schedule overall (Playing Oregon out of conference, playing the SEC title game, and playing a tougher bowl opponent). But LSU v. OSU would be a rematch and who wants that? And yet if you pass on LSU, you take a team that could not even win its conference and backed in by playing a much weaker Bowl opponent. That's a mess and everyone complains...