I want automatch to work reasonably well even for currently-weaker “25k” players that the rating system considers 30k. Let them play each other, and let one experience a win, while the loser gets to play a closer-to-50/50 game with a 31k or a higher ranked player with a handicap.
The terrific new rating system, with its better appraisal of strength, is designed to help automatch work better—i.e., for setting up games where both players have approximately equal prospects of winning. Why hurt that advantage by treating everyone in the big range with 25k at the top as if they had equal strength?
If you fear that a current 29k is embarrassed about not being 25k, I think that that is a minor issue. The 29k wants to win a game sometimes, maybe even half the time. Let him experience that. Whether his official ranking is 29k or 25k is minor consider in comparison.
And please, there is no reason to make a difference for kids. Why do so many of us want restriction after restriction on players based on crude demographic categories? Instead, please make the goal for OGS to be simple: After a new member plays his first several games, he can get a 50/50 game with automatch. Even if his current strength is bellow 25k.
Since we’re already computing ratings sometimes well below 25k, let that determine their public rank for now so they can get an interesting, competitive game today instead of forcing them to wait for months. They won’t feel a stigma of 29k or 34k if they are at the same time sometimes winning. The stigma of almost always losing is surely worse than a likely-temporary kyu label.