Hmmm...getting 2 first class seats to Bora Bora isn't easy on anyone - at least, not if you want to be on the same plane. Is this the Air Tahiti Nui connection, and the reported difficulty in getting 2 premium seats on the same plane? More of a partner problem than an AA one, I think.
I've redeemed premium long-haul seats on all 4 of the current majors and in hassle factor I'd probably say Delta is the worst. Then in the middle CO is easier to deal with but UA has had better availability. (No one knows whether they will have the worst or the best of those when they merge.) Lastly, I've only done AA once but they were the easiest.
That's setting aside domestic - just long-haul business/first.
FTF