The same logic that I said earlier applies to Sith Lords. You groom your successor and that successor either is good enough to defeat you or you destroy them. LF wants someone worthy of his love. In order for Sansa to be worthy, she must be a formidable player of the Game of Thrones.
Now, explain to me the logic of the showrunner saying LF is her teacher but you somehow believing that was not the intent? Do you think the showrunner just hates you and purposefully said this years ago because he knew that we would argue about it today?
Let me guess, the showrunner is actually the Three Eyed Raven Bran Stark trapped in the present after defeating the Night King. That's how he knew that we would one day argue about this.
Look we are going in circles. The showrunner agrees with me. Nothing short of George Martin coming on CCS and telling me the showrunner is wrong is going to lead me to accept your word over the showrunner's. Are you actually surprised by this? Again do you really expect to change my opinion because you said so when the showrunner agrees with me?
Rubbish, LF is not grooming Sansa to be his successor, and I am not into Star Wars so I won't argue the finer points of your example, it is lost on me. Again, never denied Sansa has learned some things from LF, rather, I think you are completely misunderstanding LF's intent, there is no duality there, it is binary, and it is all to further his ambitions, Sansa is a pawn in the game, a tool.
And while the show producers may have made that statement, it was clear that we were being lead to believe that at first, but it would not be the first time we were lead to believe something from them that wasn't true (cough cough jon is dead)
To LF, Sansa is the game piece he thinks will do best... for him. In order to imagine LF as the "teacher/good guy" you'd have to reconcile that with the overwhelming evidence of just how shitty an individual he really is. Entrapping Sansa in KL, making her complicit in his crimes in the Vale, and trying to isolate her affections. If he's doing any grooming, it's of the sexual kind common to pedophiles and perverts. Sansa is learning some of his methods, but I don't expect she'll follow in his footsteps, and LF certainly isn't magnanimously teaching her out of a sense of good will and concern, it is all for his personal gain, exclusively. At the very best, Sansa is one of his personal "prizes" a substitute for Catelyn, in his quest for the Iron Throne.
As for Jamie, I am not sure in your mind what a redemption arc is. Jamie is portrayed as a bad guy, then we see a different side of him and grow to like him, despite for every two steps forward he seems to take one step back (recently this would be reversed).
So let me ask you this, if he turns his back on Cersei, and joins Jon to help fight the WW's despite Cersie, is this any sort of redemption? If your answer is no, then we are never going to agree on what a redemption arc even is.
As for him dong what I suggested, there have been moments in the show, not so much dialogue, but facial expressions that to me, and many others that not only foreshadow this happening, but illustrate he is in fact slowly changing (he is,, by his own self admission, a slow learner).
he did keep his word to Catelyn, and I am sure Cersei would not approve, to find her daughters and keep them safe, albeit thru Brienne.
his facial expression when confronted by edmore, about his deeds, did give him pause for reflection and a glimpse of remorse, albeit fleeting.
again his expression when first saw Cersei after she blew up the Red Keep
And finally his expression when confronted by Olenna.
So your saying the show runners did not purposelessly put these moments in the show, to foreshadow he was starting to see the light, and this cannot be called a redemption arc?