In seven months, from the time Couladin died to the Battle of Malden, the Shaido Aiel transformed from essentially just like the rest of the clans to a lazy, drunken gang of bandits, sitting on their asses, raping their prisoners, and enjoying the good life. This happened despite there being no great upheaval in the leadership ranks (sept chiefs, Wise Ones, societies still perfectly extant) other than Sevanna prolonging her perfectly legitimate rights indefinitely.

I don't buy it. This is not Heart of Darkness. Either the Aiel actually had this kind of behavior going on commonly, outside of Rand and Egwene's view, or their culture really is highly inflexible and breaks in all kind of interesting ways when tested.