I'd suggest to make multiple spawn points few meters each from other and use them in shifted order, so people don't spawn in exactly one spot, once I shared the spot with 2 other dwarves (and many times with one), now it will be all races in one place, so it will be even worse. I think at least 5 spots would be good, but 10 would be better. Implementing should be easy, as it needs just one variable for last used position and coordinates for each position.