It was discussed in another thread that if a collared Aes Sedai thought her life was in danger she can use the One Power as a weapon, so it's just a matter of the Sul`dam figuring that out and finding ways to get the collared AS to think they in dire danger. It was also mentioned that some...
I'd always figured they were a circle of two just hadn't seen that thought confirmed anywhere. That might explain why they appear to be extra powerful vs regular Aes Sedai, not counting their rapid-fire weaving skills.
Channelers in battle are a type of soldier/weapon just like anything else on the battle field, they just happen to be very effective and versatile. That General who surprised a Seanchan army at the gates of a city using his soldiers dressed up like commoners in the surrounding fields won that...
I haven't done a lot of studying of theories etc, these are just my thoughts.
I suspect Aviendha's visions will actually happen. I'm seeing the Seanchan as a reset button: they return Randland to the days of unity like under Hawkwing, but at some point something crazy happens and... more turns...