-You can race your best time ghost on each level (this would make the high score lists even more competitive)
Racing your ghost is ok but racing other ghost will jump reveal the pattern to everyone and thus ruining the idea of the leaderboards.
How so? Just because you know a route doesn't mean you can beat it.
Mario Kart Wii for example, regardless of what you think of the game itself was wonderful fun to time trial because you could download the world record ghosts and race against them to improve your own times.
I honestly think it'd be a great thing to see!
The idea is to find the pattern yourself...