I say he's already perfect. He's a wonderful mixture of that arrogant jerk who's only really acting out from the game with the added bonus of being more aggressive towards wanting Tifa. And he's an avatar, and that reviewer is aware anyway that actor!Cloud isn't really Cloud, just someone portraying him in the game, and you've also very clearly stated that "Avatar" is AU. S/he is free not to read further if it makes him/her squeamish, and you're also not obligated to that reviewer to change how you characterize Cloud in this story.
Write him as the story dictates or however makes you happy.