Right now, the 1v1 and 2v2 ladders are set up so that upon entry, you will play against the lowest rung of the ladder. You only end up playing the top players if you have a perfect score after the first 10-13 games. This is a part of the reason why it is so easy to reach the top 10 before even finishing the provisional ratings: an alt can enter the 1v1 ladder, smash through 13 lower-rated players and stall 2-3 great players while waiting for games 14 and 15 to finish and hopefully win.

What if instead of starting at the bottom of the ladder, newcomers are paired up against the top 50 players, first? That would make it much more difficult to earn a 15-game winning streak.

Something along these lines has been suggested before (starting with a rating of 1500 rather than 0). However, there is a problem with this, in that you can join the ladder, lose two games and leave the ladder, then rejoin just as those games are expiring with your "legitimate" low rating and play against bad players anyway.