This seems to be the reason that most people do not reboot, as many of my friends are among the top of the leaderboards and do not want to lose this position.

What they should have done, was create a separate leaderboard for each reboot, and keep the regular reboot as a general for your entire Crysis experience.

This way you could still see how much better you have become for each reboot, which is the reason Crytek decided to do this, I believe, while not feeling as they rob you of a hard-earned position on the leaderboards.