Vikings were 11-5 and very good in 2015 (lost by a point to Seattle in the playoffs), but lost their starting QB in the preseason for 2016. I think you are wrong about the NFC North.
AFC South is clearly the only candidate that can rival the AFC East, now that the Colts suck, although the NFC South was pretty bad a couple of years ago. Since 2000, though, neither has been as atrocious as the AFC East.