I played around with new settings and made some more adjustments. 1) Changed the degrees to latitudes to 90 and -90 from 70 and -70. Turns out my degree latitudes for the 4 regions were right, but the total latitudes were not. Whoops, American geography at its finest. I also brought in more accurate tundra and arctic/antarctic latitudes. This makes a big difference: 70 range was 31% tropics, 18% subtropics, 39% temperate, 12% ice. The 90 range is now 24% tropics, 13% subtropics, 36% temperate, 26% ice. There is a lot more cold land, which can vary even more depending on how far north and south the land spawns in. The scarcity for ideal climate will make warfare even more likely. 2) Bumped up fish fertility by 20 from 40 to 60. This made fish spawn more often, consistently. 3) Bumped up desert and jungle spawn percentages, but for jungle to be more likely than desert. This is the best way to get the intended biodiversity, because I experimented with increasing feature % and that actually eliminated deserts completely. The minimum temperatures make it so that the range of jungle and desert spawns are limited, and also that tropical jungles take precedence over subtropic deserts. We don't want Brazil to look like the Maghreb right?