@Danoff
I don't really see it that way, at least not beyond the fact that being strong with the force could be considered like a genetic trait. The choice with what you do with that is open to the individual, but mostly that can be treated as though decided by external influence. The Jedi order seem to follow a "with great power comes great responsibility Mantra", as a side note (I appreciate we're talking about the films here but....) the book Master & Apprentice poses the question 'do Jedi get to exercise free will?' whilst Qui-Gon Jinn is Kenobi's master.... Qui-Gon comes to believe heavily in prophecy, and Obi-wan talks about accepting that choice of what to do with the power of the force is taken away by the Jedi whilst people are essentially toddlers, but that they must accept that for the greater good... anyway, I digress.
This can't even begin to become the case until ESB is about to roll credits. Up until that point Luke's just trying to do his bit to save the galaxy and considers his father to be dead... So I don't see it as a factor in Ep. IV or V. Come Ep. VI I don't think at all that Luke is seeking validation for him or Leia. He's still trying to save the Galaxy, and whilst there's no doubt the power he lucked into just by being born, kept him alive a lot longer against Vader - it's not what ultimately saved the day, it was simply the reliance that a father would not see his son killed. His motivation for wanting to turn Vader back to the light isn't as simply as validation... it literally saves the galaxy from tyranny, saves his sister, and saves his friends... if Vader stays evil, it's not a burden that Luke lives with... it's the death of him, and every he cares about, and a lot of people he doesn't care about. He's haunted by the possibly he'll end up like Vader, he sees it in the Dagobah cave, he sees it when he's whooping Vader's ass and looks at his mechanical hand... he's not trying to use Vader or the circumstance to validate himself, he's doing it to be better than his father, and hopefully to drag him back to the light, and save everyone at the same time. Lukes choice
is validated, as it works.
If the issue is genetics removing free will, then I suppose in its simplest state the story rests on the Bond between a father and son. More broadly speaking if the issue is pre-destiny then yeah, it's a problem for any film that has prophecy as a plot device.
How different is Ep IX really? Rey shuns her Evil ancestry as did Luke, but instead of relying on familial bonds to save her, her friends and the galaxy - she relies on the Force, the 'genetic' trait, she (and Ben Solo) have.
I'm not really disagreeing that 'destiny' over free-will is a plot device in Star Wars, I just think that it doesn't affect character motivations quite the way you imply. Maybe the difference is subtle... is the luck/burden of their birth what drives them to fulfill their destiny, or what empowers them to take a path they may chose (albeit with external influences).
