you both bring up good points. i don't think Banagher was any more grown up in the first episode. I think it's just that now that he has a Gundam, and is has more power/options in these dilemmas because of it, that we have different expectations for him all of a sudden. And when he's surrounded by determined, hard fighting people like FF, Audrey and even Armando, he seems childish and naive in comparison.
it would be interesting if FF ended up serving as Banagher's mentor / "I'mma make you into a man, boy!" character. Don't think there's ever been a Gundam that focused on a character switching sides so early on, not the Gundam piloting male lead, at least.
i actually hope they don't bring in too many more characters. there's already a lot, and i'd rather see them developed than just have an episodic character-swapping carousel...