Exactly. At this point the Seanchan are very much aware what holds the rest together is what they perceive as the DR/WT "alliance". In short: the channellers.

They're perfectly aware that all the rest is weak, and under the "domination" of those groups, and it's them they have to neutralize and if they succeed, all the rest is theirs. Either they'll surrender, or they're all easy takings.

There's a MAJOR factor that is overlooked regarding the Seanchan. The very raison d'être of the Return is Tarmon Gai'don. If Tuon fails to unite the world, and take control of Rand, and the LB is still won, the whole system of beliefs of the Seanchan has fallen apart, they're whole projet for the Return falls apart. Tuon might see it differently, but her people believe they're doing what they're doing because prophecies and Imperial propaganda told them they must reclaim and put to order those lands to fight and win the LB. Once this is no longer valid, there's no telling how Tuon and the Seanchan as a people will react to this or how this will affect how they consider the facts their homeland has fallen into chaos in this new light (though it's somehow more likely they've misinterpreted prophecies and will be brought to join their forces to Rand's side one way or another before the end). Readers forget too much the Seanchan mean to conquer to prepare to fight the LB, that there's no garanty they'll pursue their war of conquest after TG, that if they didn't ally with Rand before TG, this will most likely become a full-out war to capture and wipe out channellers, no longer a well ordered campaign to conquer each land with great care not to undermine its military potential too much in the process, as those people are needed for TG down the line.