Honestly, these divisions were geographical initially, now they're political. The money divisions are the NFC East and the AFC East, and I don't see those getting broken up. Miami wants to be in the AFC East because being in the New York and Boston markets makes the franchise tremendously more valuable than the AFC South, which is the least valuable set of markets in the AFC. The AFC North has a group of like-minded team playing hard-nosed, cold-weather football, and none of those teams wants Miami, nor would it make any sense. Similarly, the fallout of moving the Dolphins into the AFC West makes absolutely no sense at all. So I can't see the Dolphins moving out of the AFC East. With the Super Bowl being held more frequently in Miami than anywhere else, and with all of the athletes wanting to live in the Miami area, I can't see the AFC East anchors (New York Jets and New England Patriots) supporting swapping any other team in for Miami. Now, Buffalo, they're lucky to be in the AFC East, and I could see them getting bounced to the North or the NFC far more easily.
The NFC East is the premier market set in the NFL. New York, Dallas (media darlings and a huge following both domestically and internationally), Washington (rabid fans in a major market) and Philadelphia (strong fan base in a major market) all with geographic ties, strong city rivalries across all sports, and very entrenched NFL rivalries. No stadium is more continually sold out than the Washington stadium. No stadium is fancier than the Philadelphia stadium. Power brokers in all 4 franchises, with Jones and Mara being among the most influential people in the NFL (probably only along with Kraft and Rooney at the very top). So, nobody is breaking up the NFC East. Any London team would either bounce the Bills out of the AFC East, or play in play in a division besides the East.
Am I worried that the Dolphins might move to London? Yeah, a little bit I am worried about that, despite it being a very remote possibility. Am I worried that a potential Chargers team in London would push the Dolphins out of the AFC East? Nope, not one bit, because I just can't see it happening.
Because we used to have the "Central" divisions that now have been realigned into a North and South, there's more fluidity for those two divisions. The West has always had too much geographic distance to traverse, so those divisions have always been more geographically oriented, and thus demand some fluidity. But, bear in mind, that if there ever becomes a London franchise, the NFL will move mountains to get it a European rival, whether that's Berlin, somewhere else in England, or possibly even a second London team. So, whatever divisional alignment is reached, you'd better make room for 2 European teams, because a European rival shortly follows establishing a London team.
