As regards the sisters working vs. being in the Tower all of the time, Elaida made a summons for all sisters to return to the Tower when she was raised Amyrlin. I think this is an indication that an awful lot of them do work in the world. I think this is further shown when 1/3 of sisters are in the Tower, 1/3 with the rebels and the last third are still out there doing their jobs.
I greatly dislike Egwene, I think she is self centered, acts like Elaida yet descries anything the other woman does. I think her plot line is written rather badly too, everything seems to fall nicely into place for her, even getting captured. I can't help but think that the attack on the Tower was written similarly, to show Egwene as an amazing leader whilst everyone else failed almost completely.