Excellent video, good advice. I wanted to contribute. To me, Vader and Vegeta's redemption are very similar. I think what allowed us to accept Vegeta's redemption (and the same could be said about Vader) was the audience discovering that these tough, coldblooded fearless monsters were actually afraid of a far more evil and monstrous character who is not only pulling his strings but also capable of greatly hurting him. Vader feared the Emperor ("You don't know the power of the dark side. I MUST obey my master.") Vegeta feared Frieza ("He took me from my father when I was just a little boy. He made me do whatever he wanted and said he would kill my father if I didn't. I did everything he asked, but he killed him anyway along with everyone else.") It helps us understand that these villains are just victims of an even greater evil. We get to see both in a fragile state that we never even imagined before: Vader, a fragile, scarred, dying old man. And the powerful and fearless Vegeta crying and begging amd reaching out to his mortal enemy, Goku, as he dies. Then our hero is powerless to stop them from dying. Now that we understand why they were so evil, we wanted them to have a second chance, but they die, atoning for their sins. Yet in the end they are both resurrected and they shed their old villainous ways. Vader becomes one with the Force and finds peace, Vegeta finds love through family. So using the examples of Vegeta and Vader, here's only one of the many formulas I recommend for villain redemption: 1) Give the villain an obstacle or greater villain that he can't overthrow on his own (Palpatine and Frieza, both evil Emperors, coincidentally) 2)Have the great evil severly harm the villain (Emperor shocks Vader, Frieza shoots Vegeta) Nobody is there to save the villain from this attack. 3) Show us the villain in what I call an opposite state (Terrifying Vader as a weak old man without his mask, Tough and coldblooded Vegeta, crying) 3)The hero defeats or helps defeat that which the villain fears, and achieves something the villain has been after. This frees the villain and shows him he doesn't have to be evil to achieve his goals. (Goku defeats Frieza, becomes a Super Saiyan. Luke resists the Emperor's temptation, defeating the seductive power of the dark side) 4) Make the villain atone for their sins. give the villain one final good act where they choose to break free from evil's grasp. I agree with you in that if they participated in genocide (both blew up entire planets) then they should die. For the end of a series, if the villain has been extraordinarily evil this would be a great place to end their story 5) A second chance. If the villain still lives, he must leave behind his evil life and do good, as a hero or anti hero(Vegeta). If he dies, let his legacy continue in the light. (Vader joined Obiwan and Yoda his old friends in the Force while his children saved the galaxy from the Empire)

That was legit really interesting man, great work!