>>23342510
To come down to one specific X-Factor, I'd have to say it's how thorough and deliberate the production was. Everything from making sure the monster of the week ties in with a greater theme that reflects things going on with the main cast, the choices of animals for Core Medals matching the Greeed they're associated with character-wise, the insert songs being Character songs for Eiji and down all the way to Eiji's wardrobe. Nothing is just ticking boxes, you can tell that a lot of thought went into every part of the series. Even when they had to pivot from the original plans due to scheduling issues and the earthquake they didn't just scramble to put together "something that crosses the finish line" but the change of direction was so organic that you wouldn't even know that it wasn't the original plan.