It never made any sense to me that the Ogier could cleanse the Ways. It pretty clearly has to do with Traveling and the World of Dreams. If I had to write a story about cleansing the Ways, I'd involve Perrin and Egwene, and make it a set piece for Asha'man, Wise Ones and Aes Sedai cooperating as equals for the first time to achieve something important, and prevent further surprise attacks from Trollocs on other cities.

That would have been a way more meaningful addition to Memory of Light than the endless, stupid, unremarkable battles the book is filled with.