It's even spelled out by Moridin in TGS.

I already predicted after their first meeting in KoD, though, that Semirhage won't have a chance against Cadsuane. Now Cadsuane gained even more reputation as "the Aes Sedai, who spanked Semirhage".

Regarding Egwene, one certainly has to say that her capability is the most unrealistic from all the Two River folk. Rand, Mat & Perrin are at least ta'veren and have special abilities to explain their raising (especially LTT's memories; Mat's luck; Wolfbrother senses). Nynaeve is super strong and was already a Wisdom for some years.

Egwene, on the other hand, is just a young, not that strong channeler, who served in a tavern before, as the daughter of a little village's mayor. Ok, she made experiences, like being damane or under the Aiel, which hardened her, and she is a Dreamer, but that doesn't really explain, how she can easily outsmart almost all AS, IMO.