Definitely not Southwest since you want international. I think AS is a good idea, as well. Credit to AA. AA still has excellent value for international business and/or first class awards. Read some travel sites, stay current, and try to get to Oneworld Emerald, which is the "sweet spot." All the carriers and programs have lost value, but it is still possible with AA to find a one way award to Europe in a lie flat for 57,500 Advantage miles, for example. Yes, flexibility matters, but there is sill consistent availability. Also, there are good last minute awards.

AS gives him the flights he needs on the itinerary he needs, but AA gives him (and you) the most likely options for future gateways at the best value (especially with all the changes).

I'd also say, since status is spend-driven, getting the credit cards does help a lot, unfortunately. Rumor is AA is dumping Barclay (terrible card and terrible bank--IMO). That said, you can get that card, earn your 60K spend bonus, and wait out the card dump. The Citi card options are vast. Executive card has a high AF but comes with Admirals Club access. I like it (obviously, people have varying opinions, but AA does have the more generous access/guest policies as well--here's hoping that stays for a bit...)

Oh, and welcome to FlyerTalk!