It doesn't have to involve the Towers of Midnight themselves, last spring Harriet discussing briefly the outriggers happened to confirm that RJ had tons of notes for Seanchan and didn't intend to bring us there again in the main series.

ToM in Imfaral was where the a'dam was presented to Luthair(IRRC) and I vaguely remember something about it being his original capital before the move to Seandar - and it's the book in which the whole Paendrag stuff may finish to come full circle.

This also ties to the 'three towers' in Tuon's omen, which pretty evidently represent the White, the Black and the Shadow's Moridin is fortifying in TGS.

Tuon still sees the White/Black as her enemy, when the light has to unite against the Shadow. It's also fairly obvious the BT story line will come to some kind of climax in the next book, it's more a question of who will be aligned with whom and who fights whom in that battle - my personal prediction is a three-way fight: Logain+Egwene vs. Taim and the Seanchan fighting both sides in that battle).

Then, there's the Tower of Ghenjei in the next book.

IMHO, Towers of Midnight won't have any major tie to the Seanchan building, and at best some mention of it in a specific historical context. It's most likely a thematic title, like Crossroads of Twilight - where people were speculating about which crossroads Perrin or X would come too, and Knife of dreams that sparked two dozen silly theories about what knife it would be. Midnight is coming for all the towers - Tarmon Gai'don starts in the climax of the next book, and all the main cast is reunited. Normally, that should include Tuon - and nothing says she'll have made the right choice by then (or until then).