So, as I said in the Subject, I think that the 13k rank that people start with is doing actual harm in the system.
As a high DDK (19k) I experience it.
I am seeing a stream of players who have played only a few ranked games, which I encounter either via challenges or their posts in the forum asking for help, and they appear to be mid-DDKs - IE quite reasonable players - but in fact they have little or no clue.
This does everyone harm. The people themselves end up matched with people who whip them. That’s not good for the beginner. And the opponents who are paired with them have to play a game that they were not expecting.
Also, though less pertinent, the initial uncertainty is too low. A new player joining OGS is really 25k. So 13k+/-6k is a way overestimate, even in the worst case. It puts them at 19k at worst. 19k is dramaticallly different to 25k.
My opinion is that the only workable option is to ask people what they think they are when they join. Any attempt at guessing and using the “uncertainty” to compensate just doesn’t work in practice.