My fear is a devaluation with AA/US as well. Last summer I got the Barclay US card for the signup bonus, once we are able to transfer miles between accounts I can combine and go for that F award on Qantas. Hopefully we are able to combine and I can book before a devaluation.
Looking to cancel either my Citi or Barclay card this summer once the annual fees on both are due. I am probably going to keep Barclays unless something changes before then. The 10k annual bonus plus companion certificate while I get no annual retention bonus with Citi seals the deal for Barclay.
Although when that devaluation comes I may just say enough with airline miles and go for a travel based bank card like Citi TYP, Capital One Venture, Barclay Arrival, etc and just make the only airline miles I earn BIS miles. If airlines get too greedy with the devaluations and people move to bank travel and other cashback cards and the huge revenue stream of banks buying miles and the airlines lose that cash cow they will regret all the devaluations. If people stop using airline cards that'll learn 'em.