One thing to remember is that the Aes Sedai do have enemies. Part of their strenght has been that whent they are out and about they are either along except for their warders so they can slip under the radar or they travel in force and are too large a group for any enemy to take on.

If you have seven Aes Sedai in every major city/town they would be spread very thin. The Seanchan or the Shadow could pick them off city by city.

I agree that with the taint gone the Aes Sedia don't have as much to worry about having male children but its still a problem. If they do have male children who will train them, another sisters's Asha'man warder? What if the Black Tower gives an order to its Asha'man not to train anyone but to insist that if they want training they have to go to the Black Tower.

Sisters do not really trust the Black Tower yet, would they be willing to sent their son's there? Lastly how is Egwene suppost to order any sister to go and have babies for the good of the Tower. That sounds very close to prostitution.