Fyodor I like your style and long thought something similar but mine differs:
Rand does really permanently defeat the DO by taking his place becoming the new lord of death, or more accurately death and rebirth, as foreshadowed by his title Lord of the Morning, his attempt at resurrection in tDR, and the Tinkers with the song as the true People of the Dragon. No seal will be required and thus Rand will be both dead and not gone. Posted this on Theoryland many years ago but can’t locate it anymore.
This will be accomplished through the 3-1 theory that Rand, Moridin, and the DO merge.
Callandor will be the key by – allowing Rand to wield even more power than the CK. Its remaining secret is it facilitates a limitless circle at any range, enabling Rand to tap into its power plus the cumulative power of every remaining channeler. This brings us full circle from the prideful Companions assault on the Bore to a cooperative, full force effort to defeat the DO. Kumbaya
Callandor will only give Rand enough power to force the merger. He doesn’t have enough will to wrest control of the 1 body from the DO, or the DO and Moridin.
Tuon using the power of the Crystal Throne, her indomitable will, and her life time sul’dam training, in conjunction with Matt’s luck/ta’veren-ness takes control (like using an a’dam/compulsion mix) of the struggling, merged Rand+Moridin+DO, giving Rand the support to subsume them.
Who the freak has orchestrated all these pieces to work together? The creator; the pattern; someone else; is Moridin a closet Lighter setting up the ultimate double-cross?
A new cycle will begin with Padan Fain as the new, lesser great force of evil, ala LoTR/Silmarillion.
The Wheel turns out to be not a continuous circle but a spiral with both repetition and direction, easily mistaken by Randlanders as continuous repetition. Thus RJ has been both truthful, cycles and repetitive Ages are real and permanent, and deceitful, change does happen.
The BT circles will be overcome either by surprise (to the darksiders) use of the “dragons” or an additional circle related ability of Callandor to take control of formed circles. (OK I am grasping but the atomic level power of single circles let alone multiple is something I struggle to reconcile with anything but the end of time.)
Cadsuane is going to beat down the outted DF, Sorilea, when the WO tries to ambush Rand.
This will be the book where people actually talk, listen to each other, and act reasonably.
Taim is a non-Forsaken, War of Power dreadlord somehow preserved like the Forsaken to the current Age. Sure Taim could be Moridin, but his day job manipulating the entire world seems a bit too intense for moonlighting as a DF mole running the BT during its rapid expansion.
Rand built the Black Tower with a secret motive. He intended that it would be infiltrated and that he would use it as a trap to eliminate the new dreadloards, or at least give him the advantage of knowing where 90% of the new dreadlords are when the Last Battle starts.
Screen time for the Tinkers and the reveal of the Song will be short, sweet, and a calm spot in the eye of the maelstrom of action.
The Maidens will make a final stand at Shayol Ghul to buy Rand time, getting wiped out to a woman. This includes the Bain, Chiad, and Gaul love triangle. Ok so I probably missed a Min viewing on that one, so sue me.
Some crazy, rich WoT fan will bribe a Tor employee for the manuscript and leak it. Not only Tor, but WoT fans will be devastated.