Lit Which Jedi turned Sith has the best downfall/redemption?

There is no "unifying Force theory". Under the TPM-era conception of things, the unifying Force is an aspect of the Force which complements the living Force. It is not a competing philosophy ( despite erroneous claims made by the JATM and any other sources like Wookieepedia that have quoted the JATM ).

 

That's basically a tenant of the Potentium, the full thing being that the Force is inherently good, and the darkness doesn't exist within the Force, but within the person. It is then projected onto the Force by the actions of said person. The Dark Side is a perversion of the natural order of things. The potential for light and darkness all comes from the user, not the Force.

I love Jacen Solo's journery, but his fall was handled awfully.

 

I saw it potentially coming since Traitor. But already before that, Jacen showed several times that he had a tendency both towards the extreme and a need to define himself as difference on large expence. He could still have taken different roads - even after his capture, I think, but instead he distanced himself more and more. I think his fall was very well made.

I've also enjoyed Vestara's character arch this far. And one I'd enjyed the snippets of, but hope we'll learn more about, is Shira Brie/Lumiya. Not necessarily her life between the Marvels and LOTF, but her life before we meet her in the Marvels. There's a small short story (or is it even a piece of a game?) where she's shown pretty brutal in her youth, but that's all. I'd love to read more about her!!!

 

From Vector Prime to Balance Point- he seemed pretty unwilling to compromise on his views about The Force and the proper role of Jedi.

 

That's "tenet".

 

Some of Darth Sidious's remarks to Maul in The Wrath of Darth Maul seem reminiscent of JATM's "Unifying Force theory" without actually sounding like the Potentium.

"rather than embrace the full spectrum of the Force, the Jedi ignored the infinite shades of gray that stretched between light and darkness. They declared the light side good and the dark side evil. To them there could be no in-between, no middle ground."

"It's one thing to examine an energy field that permeates the galaxy. But to give an energy field characteristics of good and evil? One might as well say "This cloud wants to protect us from solar radiation, but that other cloud wants to strike us dead with lightning."