Egwene isn't entirely devoid of memories from past lives. Her ability to understand Manetheren battle cries notwithstanding, she does things with weaves that no one has taught her to do (i.e. "tying" a light to the wall as a novice) and she shows an amazing capacity with the element of earth, which hasn't been seen in women hardly since the breaking. She may not have even been reborn, but her ability with Cuendillar has been used as a plot point. She figured out how to get into TaR physically (plot point) and she rediscovered Traveling (pp). If she IS someone special reborn, it's more than already paid for itself even if she doesn't have any further epiphanies.