Maybe a delta guy can confirm this, it sounds like premium trips are plentiful. American goes to great lengths to avoid premium. Delta seems like a better job right now. AA has the seniority advantage but I think deltas better contract makes up for it. Plus delta has faster upgrade and the commute from stl is probably easier at delta.
It is a completely different job living in base. If you can move to any of the bases go to the corresponding airline and don’t look back.