It's partially hipocritical to call the Cloud supporters fanboys then say Sephiroth could kill Cloud. If he could he would've, but he didn't in any of his 3 attempts. Plus, just because Cloud is the good guy doesn't mean he isn't stronger. He is stronger because he is the good guy. And anyway, in stories it's whoever has the strongest will who wins. Sephiroth had no reason to fight, no one to protect, but Cloud had to win to protect those he cares about.