If Rand had balefired that many of the Seanchan, he would have almost certainly destroyed the pattern-- especially since he was using the Choedan Kal at the time. Therefore I think it is very good that he didn't try to balefire them.

The WoT Encyclopedia states that the Tower of Midnight is in Seanchan. It even says what city the Tower of Midnight is in.
I don't think we can make any theory about Tuon without considering that she may be making a trip to Seanchan-- especially now that she will have Traveling.

Tuon is very hard-set in her mindset. I think it will take something very powerful, possibly traumatic to change Tuon of her perspective. There are several possibilities I can think of-- but some of the more likely ones may have to do with Tuon being placed in an a'dam, or possibly with an Aes Sedai saving Tuon against an attack.

Something fishy is definitely going on in Seanchan. The people who are vying for control there are not going to be very receptive to seeing Tuon coming back and trying to regain control (if Tuon does indeed go to Seanchan).

Since Semirhage murdered the Imperial family in Seanchan, I am thinking that another Forsaken is now working to control events in Seanchan. Moridin could have sent Moghedien or Lanfear to do the work. Or Demandred himself could possibly be there now. The Forsaken have probably been working furiously to claim some of Seancahn ever since Semirhage was captured by Rand.

Also Rand is supposedly going to bow to the Crystal Throne, then this indicates he may go to Seanchan himself at some point (unless Tuon has it moved to Ebou Dar via Traveling).

I am predicting something big will go down in Seanchan in the next book involving the Tower of Midnight. I also think that this event will have seomthing to do with Tuon changing her stance on a'dam. I can also easily see a Forsaken there working to manipulate events against Tuon.

Just a few thoughts.