I'll take a CO/AA alliance over a merger if only because my firm has a love affair with AA.
CO is our secondary preferred carrier but getting around the AA bias and AAirpass deals is like getting a Continental agent to reroute a ticket with the $50 standby. Perfectly legal in the system, but not worth it to educate them in practice.
Would be nice to be able to earn OnePass miles while taking advantage of our JFK-LHR deals where we're allowed to book AA first class for the price of heavily discounted business ($3000, fully refundable).
Continental's rationale for merger has always included the need to keep corporate contracts intact -- they seem to think the corporate contracts will follow whomever has the most comprehensive network.
Still doesn't fully answer the Asia question. But the Dreamliners coming online could eventually address a lot of that.