(The show is really good. It took me a while to actually start watching, but people are right in that it's much better than the PT in every way.)
I've watched Season 1. So far it's just "okay."
I don't think any Jedi as they were trained in the PT would've tried to save their father like Luke did. Luke, unlike many of the Jedi, had emotions. Maybe I'm misinterpreting Luke trying to have Vader redeem himself as an emotional plea to him, but that's how I took the scene.
You can think of it this way:
- The Jedi see themselves as diametrically opposed to evil/the dark side. Because Anakin turned to the dark side, Obi-Wan's response is to "do as I must" (i.e. kill him). We see in the OT that neither Obi-Wan or Yoda believes Vader is capable of redemption, because "once you start down the dark path, forever will it dominate your destiny."
- The Sith see the dark side as a necessary ally. The Jedi are, conversely, an obstacle to peace and freedom because they take a narrow view of power and the Force that abstains from personal desire and ambition. Thus, they must be eliminated in order to achieve true peace and freedom.
- Luke represents a kind of middle way: instead of believing that the dark side must be destroyed, he believes his father should be offered a chance at redemption. Notably
this is not about embracing both the light and the dark side:
Never. I'll never turn to the dark side. I am a Jedi, like my father before me.
And this is really his most major departure from the Jedi: that he doesn't believe that his father is fully evil; he believes there is still good in him. Yin and Yang, not just Yin. What breaks Vader in the end is ultimately his realization that he's not resigned to simply walking the path of the dark side. So for Vader it's the same: he's not wholly Yin - he's not stuck in dark side mode for all eternity - he still has some Yang in him.
This is a radical difference between Luke and his teachers, but it's not the same thing as "balance to the Force" meaning "equality between light and dark" or that you must embrace the dark side to achieve balance.
And that's kind of how I read that Yin-Yang scene on Mortis. Notice that Anakin is being offered a definitive ultimatum: choose one or the other. The view that the light side and dark side are definitive ultimatums
is an incorrect and flawed view; Anakin isn't locked into one or the other for eternity.
When Anakin "fulfills the prophecy" it's when he kills the Emperor. It's a fulfillment of the prophecy because he eliminated the cancer that was twisting the Force to his own ends. The natural balance - the will of the Force - is restored/fulfilled. The connection between the Yin-Yang imagery and his status as the chosen one is important because
he moves between the two sides to fulfill that destiny. His destiny
isn't "forever dominated" by his choice to "start down the dark path."
What's more: even Luke has anger in him. Obi-Wan remarks that he was much the same way. The OT still makes it clear that not letting that anger consume you is a virtue. It doesn't pretend that Luke almost killing Vader out of fear and anger was a good thing. What happens, of course, is that Luke
masters his own fear and anger, and likewise for Obi-Wan, and in end even likewise for Vader. It's like the common wisdom about courage: it doesn't mean not being afraid, it means pressing on despite your fear. Both the fear and the courage exist side-by-side; indeed, they depend on one another.
I think that's ultimately what we're supposed to take away from the prophecy.