The Sun Belt will play divisions and an 8-game schedule. Since college football has been playing a 12-game schedule for several years, there will be 4 OOC games and no need for a 7-game conference schedule. The perception of the Sun Belt has risen greatly in the last two years and is already equal to or better than the MAC or C-USA. In the 2016-17 bowl season, the Sun Belt finished tied for 2nd with the Big 12 behind 1st place ACC.
But why missing out facing one more conference member due to an 8-game conference schedule, when the Sun Belt could apply a full round-robin schedule, like the Big XII has applied?
The conference likes the flexibility that 4 OOC games gives them. Each school uses those games to help fill their own needs. Strangely the Sun Belt does not use a full round-robin in baseball, one team is missed each year. Missing one conference mate does not seem to bother anyone.
If they were to go to two 5-team divisions, it seems they would have to split up Troy and South Alabama (one in the East, one in the West).
In which case, they might then implement the "rivalry" game in the schedule, which would pair Troy and USA, but not really be that much of a rivalry for everyone else.
Troy will be in the east, South Alabama in the west. Five permanent crossover pairings with one obviously being USA-Troy, don't know what the others will be.