If KE is fine with ST, then there would be no reason for it leave the alliance. Plus, I am not sure there is much to gain for KE to switch over to *A.
LAX
I agree. The calculus *might* be different if OZ was the surviving carrier and/or played an important role within *A, but KE has a pretty sweet gig in ST, given their lack of a Japanese member airline. It should go without saying that split alliances would be really dumb, even if feasible (probably not after they combine AOCs).