A one-way international ticket is the perfect use of AA miles, which allows for one-way rewards at half the cost of a roundtrip.

Are you travelling on to a third destination? It may be more economical to price the ticket out as a muti-city ticket vs. two one ways.

Worst case, you can buy a round trip ticket with a return date that you would consider feasible for use. If and when the inevitable schedule/equipment change occurs (hopefully after you have already departed) you may be able to obtain a refund of the return (or perhaps a reschedule).