I don't think rivalries matter to the big boys anymore. I don't think Clemson-BC is a rivalry even though it's on the ACC schedule. I'm guessing real rivalry games like the Iron Bowl, Bedlam, and maybe even the Little Brown Jug will get played as a non-conference game if Auburn, OkState, or Minnesota can't make the cut.
The Iron Bowl seems kind of bullcrap if one team is a professional football team and one is playing college football. I just have a hard time seeing a "good teams only!" league forming. I think there's 3 power leagues formed once the ACC officially dies and the rest are like you said chugging along as normal. Relegation and promotion would be really fun but don't think US sports leagues are up for that.
