I honestly can't think of a single way to improve the original game outside removing the tutorials, and use of the DS mic in Giant Battles. Fawful is truly one of the greatest villain characters one could ever ask for, beginning as a grunt in superstar saga and working his way up to the very top on his own. Fawful is a villain who earned ever bit of power he obtained through hard work and planning, and the threat he poses, unlike so many other villains, feels as if your entire kingdom truly is endangered by the end of the game. His quirkiness, reflected in the game's overall charming and humorous characters breathes incredible life into the franchise, and takes the Mario canon in a direction wholly unseen before. Meanwhile Gameplay as the Bros, and moreover Bowser, is consistently enjoyable, with amazing soundtracks, unique mechanics, and a battle system that you always enjoy and almost never find tedious. The finale of this game bring everything seen in the game to the table, with an iconic score, entirely epic feeling to it, and every imaginable mechanic in a fight that is symbolic and ironic of the very thesis of the game as a whole.
Truly a masterpiece.