The junior new hire base has shifted around over the years, at one time most new hires had to do a month or two in places like San Juan or Atlantic City, and for a long time it was almost a guarantee you would be in FLL. If the merger wasn’t a thing, all it would take is a glut of new hires from the west coast or another base opening and it could easily shift back east. Yes red eyes are common but it’s not like they are entirely avoidable in any other base.