Now onto my question: why is Talos so important in terms of his existence in the divine? Is it because of his mantling of Akatosh? I don't fully understand how he fortifies the Wheel yet.
*Disclaimer: this is my theory, not widely accepted at this point.*
Muthsera,
It is my humble opinion that Talos is a "Ghost of Shor" that has ascended with a new Heart, that is, the heart of his enantiomorphic other self. Lorkhan's place reaffirmed.
Additionally, Tamriel is known as "the Arena" and "the House of Sithis". Talos is a god of war, and the fluidity, chaos and change of war is a good depiction of the First Chaos of Sithis/Padomay.
A Heartless Lorkhan means that time remains linear, which is what the elves do not want. Lorkhan's place is filled, but with a being that does not need Lorkhan's Heart. The Wheel is fortified, and returning Lorkhan's Heart will no longer return the world to Dawn Era nonlinear time. Talos, therefore, must be removed before the freeing of Lorkhan's Heart can have any effect.
But gods (at least the Divine ones) live on through their "aspects", that is to say the mortals that mirror them (i.e., their "blood"). The Imperial race are aspects of Talos, therfore they must be erased before Talos can be erased.
Conclusion: not only must the Empire fall, but so, too, must the Imperials that make it up. Once that is done, then the Wheel can be unfurled.
___The Word Merchant of Julianos