I'm just going to point out that Moiraine barely spent any time in the Tower after being Raised and Cadsuane never wanted to be responsible for it - she just wanted adventures.

It's not surprising to me that the two most heretical Aes Sedai seem so willing to write it off in favor of other goals.

This really shows the maturity Egwene has developed in contrast to those two other Aes Sedai - she started being happy that the Tower broke because it would not longer threaten Rand and she ended up almost weeping as she saw the cracks separating Aes Sedai from Aes Sedai. Unlike Moiraine or Cadsuane, Egwene was given a stake in it's fate, and it seems to me that she exceeded the other two women because this stake gave her strength whereas Moiraine had her cause (running away rather than becoming an Aes Sedail Queen) and Cadsuane wanted her independence (running away a few times to avoid larger responsibilities or duties).

It's not a dig at either women, but it's no surprise to me that the two Aes Sedai who ran away rather than serve it in the ways that it were needed look at it as ridiculous even while holding to it's philosophy while the younger woman who saw her potential for greatness cut off and than re-ignited when she became the Flame of Tar Valon (pun intended). They all have their places in the Pattern, but it more of a measure of adopting causes they individually deem as just, and Egwene's became the White Tower while their's were in other places.