It is not as simple as that. In tweaking rwgmixer.xml wilderness counts, I found there is a max count at which it stops successfully finding locations for for prefabs. Don't yet know what the limiting factor is. On a 10k I can get over 600 to spawn, so the Wilderness Many setting for that is now 750, up from 400. Many is now 450 on 8k. Reducing mountains also helps as that does limit some prefab locations.
Hopefully less often, but there is no guarantee some tech issue requires changing data formats in a way we can't make backwards compatible. Ideally we will load/convert what we can instead of nothing at all.