I feel having a differentiation below 25k is great.
When i started playing Go and registered at OGS i was 51 Kyu. It was rewarding for me to see a progress in rank, first starting out at 13x13 boards. I experienced a difference between 35k and 25k. And i believe having an early recognition, and therefore reward, of player progression is especially important in a game with a very high entrance skill barrier.