Nobles usually offend our sense of democratic ideals, but in this fictional world, Egwene and Elayne fully expect the era after Tarmon Gaidon to be very chaotic, as was indicated in the prophecies. For example, Elayne wanted the Dragons because she expected an invasion by the Seanchan to occur before, after or simultaneously during Tarmon Gaidon. Egwene for her part, knows that the Hall still opposes her but her job is to unify the White Tower despite their small-minded bickering. Remember - Egwene was the one who despised the idea of keeping monarchs in the Tower for their "safety" (i.e. a political prisoners who would be indebted to the White Tower for their protection) and is building a coalition that will unite every nation into one force for Tarmon Gaidon, and to fight the Seanchan.

So neither woman is sitting around trying to collect more power just to do so - keep in mind that on the subject of Cairhien, both consider it a mission to stabilize that nation because for Andor, if the Borderlands, Tar Valon and the Northern countries fall, Cairhien would leave their northern borders vulnerable while Egwene is concerned about Tar Valon's southern borders.

In my opinion, these women are thinking beyond the Last Battle, because the future is very uncertain.

P.S. I was actually glad when Elayne started thinking on such a large scale - especially given that her blood line gives her a good claim to the throne of Cairhien and that for better or worse, if Andor didn't gain control over the Dragons, some other nation would. You can't stop the world from changing; all you can do is try to make sure you aren't made obsolete or caught unprepared.