Allow me to offer a correction: limitation to Y/B/M fares internationally has been the Delta way on SWUs for more than a decade. More subjectively, twenty NW flyers are complaining because that's what they do, right down to getting new leather seat covers and first seeing a DL logo on boarding pass for a NW-operated flight.

No question, the AA first class experience is consistently better than the NW experience pre-Delta, from seat construction and seat pitch to consistency of service. The trade-off is that mid-tier elites on AA will be paying for domestic upgrades, particularly if the flight mix domestic:international is high, demanding lots of sticker use.