A leaderboard reset would mean a stats reset. If you worked incredibly hard to get thousands of wins over the course of several years and then, suddenly, your stats got wiped because other players barely get the chance to get to that amount, would you be happy? Poof. Your hard work, suddenly reduced to atoms.
I don't see how this would be a good idea. I'd rather suggest a weekly and/or monthly leaderboard on top of the already existing one, instead of this. Even so, it is not entirely impossible to reach the leaderboard, even if you start grinding now. It will just require a lot of hard work, just like the current leaderboard players have put in.
