I think you're giving Egwene too much credit.

I mean, seriously, from her very first appearance (I refuse to read Ravens; I can hardly stand Egwene's chapters in the series, I'll be damned if I'll spend money for MORE Egwene) she's busy getting mad at Rand for something he doesn't even do! Mat says something and she gets pissed at Rand.

She's just a complete bitch, and, to be honest, I think that was RJ's whole point. He wanted to show that tyrants, hypocrites, and even complete, utter bitches, can be used to serve the Light. Sure, the Light may have to resort to some unorthodox tactics to make them useful, but as long as they're not literally evil, then they can be used for good.