We've all been hosting that game where you, at a high rating have hosted an 8 player game, and decide to read on some blog or the forum, waiting for that pinging noise of your turn, and when it comes to it, you find you are stuck with 1200-1400 players, wishing you had checked every 10 seconds.
Everyone would love this. Higher rated players could just set it and bam, knowing theres a long wait they just have to wait without fear, ready for a close game with equal levelled players. The same goes the other way, with less-experienced players being pitted against a group of higher level players that are often intolerant of them. This would make the game feel a little bit less of a minefield
Basically same as level setting, but for rating, and having the option of min/max