I don't think there were that much packed in that anime. It is pretty episodic too. But I don't feel it needs to have a lot to be good. You know sometimes people ask whether or not anime is art? What they mean is, when you produce something to appeal to a certain audience, to have commercial success, when you copy tropes and tricks from older shows and use generic story-lines and archetype characters - can you still call it art, or is it just a manufacturing? So coming back to FLCL I think on manufacturing to art scale it is much closer to art than a normal anime. It tells a story of growing up and it does it in a very unusual and unexpected manner. Also it is just a funny show to watch.