There is a mod "Rock strata variety" which makes rock biomes more reasonable. And about polar equator distance I believe there is like 5 (I may be not right, just my observation) distinct climate zones starting from arctic, then colder temperate (mainly pines and birches, few oaks and maples), cold desert, warmer temperate(redwood, bald cypress and lot's of maple and oak), hot desert with cactus and termites and hyaenas, and tropic with bamboo and fern trees.
Probably it's not all, and it's only about temperature, because there is also difference on rainfall and same temperature with different rainfall gives different biome. But in world with 25k polar equator distance it's about 5k blocks for one climate zone.