... given the personality types drawn to those 3 Ajahs, and the more obvious need for strength re the typical activities performed by their members. That would rule out Siuan (as, IMHO, would the original comment that it's an old-school, and old, AS).
I think it's less likely to be a Yellow too, since strength is often useful when Healing.
It seems to me more likely to be a Write, Brown, or Grey. Terez' comment that the reason is rare / not general implies that there is something peculiar about the specific AS (more than just her Ajah choice) at work here. But I would think "peculiar" AS would be drawn to White/Brown/Grey more so than to the other Ajahs, so I'm still inclined to look amongst those 3 Ajahs first.
Yes, I realize that I'm responding to a thread a year too late 
Few thoughts ... We've seen tons of weak Reds, Greens and at least a couple of Blues. I'd say a Red wouldn't surprise me as much as a Blue, Yellow or Green because they are less politically motivated most of the time. Even someone like Pevaara wouldn't shock me because she chose to abandon most of her political aspirations when she chose the Red instead of the Green. She had to realize she would never attain the Stole once she made that decision.
