Treasure Planet suffered from the exact same flaws as Atlantis: it was an action adventure battling against the constraints of the Disney Formula. Three and a half annoying sidekicks (the first one is allowed to become less spastic once the shape-changing blob of snot shows up), generic human designs... nice retro-tech, including a half-traditional and half-CG Long John Silver. And lots of death by falling. Lots and lots of death by falling. Oh, and some poorly-lit scenes where you hadn't the faintest clue what was happening.
Oh well.