The OP's issue actually seems to have had a pretty positive outcome without having to have have put in much effort given the alternatives! (1) A pro-active call before showing up at the airport and finding out that there was only room in coach (2) Routing retained in business TATL - albeit a couple of hours more or less on similar aircraft (3) $1K of AA funny money.
No need for a drawn-out back/forth about releasing award seats, courtesy compensation, or an otherwise stressful airport arrival surprise. The possible last minute FAM seat allocation could have happened on any US carrier so it's more of a question of looking at how AA handled (which they seemed to have done quite well).