I would be fairly comfortable with a 1h20 connection at pretty much any US airport, particularly one where re-clearing security isn't required.
If you are concerned then formulating a re-routing plan to give to the AA agents if you encounter a problem is a good back-up. If you're in domestic F, followed by TATL J or F, then on a short notice routing change you might find you need to accept a downgrade to Y on the domestic leg to route through another US airport - ORD & PHL are decent alternatives, but there are others. AA might well also be persuaded to book you on a direct PHX-LHR service which leaves later - resolving on the day IrrOps is something they're much better at than BA, most definitely in the lounges where they can be incredibly resourceful and helpful.