Cloud from FF7. The dude does change. In advent children he's not the same
This is why I hate Squall from FF8. He doesn't change throughout the game and doesn't become a better character. It's one of the reasons why FF8 is the worst game and FF7 is at the my top five. I think Cloud's change is not the reason why Lightning's character comes off so dull. She's the female version of one of the dullest characters in all of the Final Fantasies, Squall.
If they had modeled her after Cloud or Zidane this game would be a whole lot better and wouldn't need multiple consoles just to sell. I mean FF7-X sold millions of copies while only being available on 1 Console. It took FF-13 multiple consoles just do that.
If Enix wants to get back on the ball they need to make their main characters more entertaining and not a dull douchebag with a cool infinity plus one sword. It's so obvious to gamers yet so elusive to Squeenix.