that while the Seanchan have many Damane, many are not going to be strong enough to Travel. The Aes Sedai have no such issue. They can make thirteen of the weakest women link, and they'll have a super-gigantic Gateway through which their armies can move through extremely quickly. The stronger Aes Sedai can be well rested, and immediately ready for battle.

With the Seanchan, the strongest women are going to be tiring themselves out holding Gateways. Which will leave the weakest to face the stronger Aes Sedai, and the Aes Sedai will obviously link to face them, because Egwene demonstrated at the battle of the Tower that the Seanchan are particularly vulnerable to circles. They cannot use shielding at all against these women, but the linked sisters will be able to shield the damane with ridiculous ease, thus removing the OP from the equation.

Look at how Chanelle and seven other Windfinders linked and shielded seven unlinked Aes Sedai with no major effort at all. Against circles, individual channelers are at a severe disadvantage. Add to this the ability to hide your channeling and invert your weaves (which, having never heard of them, the Seanchan are unlikely to demand from Elaida), and if the Aes Sedai should so desire, they can make the damane totally useless.