I am only spoilering the responses because they are.
Warning: Spoiler! (Click to show)
Originally Posted by El Argentino Warning: Spoiler! (Click to show)
Anakin turned out of fear of losing his wife. Luke, I assume, would turn out of a similar, longstanding frustration. Sure, he doesn't gravitate towards power, per se, but you have him latching onto an idealistic rebellion, who after fighting and suffering so much (some 30 years after blowing up the 2nd Death Star) still don't have reign on the galaxy apparently - inasmuch as the Rebellion is now the Resistance, and the Empire still the First Order. The status quo hasn't changed (based on info we currently have). I'd get kind of frustrated with my life work going nowhere. Skywalker wants to "bring order to the galaxy"?
I don't even want to talk about the new movies, but Hayden Christensen's character was a megalomaniac and a borderline psychopath. Use him to explain school shooters or Nazis or something.
Luke, on the other hand, doesn't seem to care too much about the rebellion anyway. He deserts in The Empire Strikes Back so he can go learn look for Yoda. He only goes back for his friends. Then he deserts again in Return of the Jedi so he can go try to save his dad. He only fights at the end because he thinks they're going to mess with his sister.