This is one which I think I've figured out. Super Mario Sunshine is not a bad game. It simply failed to capture our imaginations the same way that Super Mario 64 and Super Mario Galaxy did. In Super Mario 64, nearly every level was unique in its presentation and theme. Even similarly-themed levels had enough fun challenges to be distinguishable from one another. Yet the first half of Super Mario Sunshine seemed to focus too much on the tropical theme and cleaning up paint. Think of it as getting a job as a janitor at a Hawaiian resort: it's wonderful at first, but it eventually returns to just cleaning up other people's messes.
But here's the rub: all of these cons become less present as the game goes on. The levels become more diversified, the platforming becomes more unique and challenging, and the "clean-up" sections become much smaller just as they were becoming less annoying. Yet without hooking players immediately, the game will unfortunately be remembered as a lesser Mario.
