AA has no doubt gone downhill but they are nowhere near as bad as UA was during the Smisek days. I left UA for AA because of how bad UA had became and with all the capacity cuts they made on the routes I fly from PIT.
So, for me, as long as AA continues to have nearly 2x the flights UA or DL has out of PIT and they don’t fall as low as UA went then I don’t see any need to move my business to Delta. Plus SkyTeam is the worst global alliance out there by far and international travel takes up a good chunk of my annual travel patterns.