With this topic, I have no idea how to actually balance this out, so I won't try to, I'll just throw out some ideas and let you guys discuss it.
Anyway. I was thinking that perhaps rather than the game picking at random from a certain number of biome presets, it could choose a temperature and tree density according to some kind of rarity index thingumabobber and let most other stuff - height variation, ore density (!), existence of certain ores, maybe just Redstone and Emeralds (!), amount of rain/snowfall, amount of lakes, etc. - be picked completely at random between max/min values.
A third group of things - tree type, tall grass/fern density, existence of vines, etc., should be picked sort-of-randomly but only within reason for the temperature and rainfall level - for instance, in a VERY hot (end-of-the-scale), wet biome, you could have either just oaks, just jungle trees, or a combination of the two. In a mid-temperature and rainfall level biome, you could have birches, birches and oaks, oaks, oaks and pines, or just pines.
Biomes such as deserts and swamps can stay the same, though, since they are "different" and should stay that way. If ground type and existence of mini-islands were randomized features, you'd get odd results. (same if the swamp grass color could be randomly selected. Ugh.)
Anyway. I was thinking that perhaps rather than the game picking at random from a certain number of biome presets, it could choose a temperature and tree density according to some kind of rarity index thingumabobber and let most other stuff - height variation, ore density (!), existence of certain ores, maybe just Redstone and Emeralds (!), amount of rain/snowfall, amount of lakes, etc. - be picked completely at random between max/min values.
A third group of things - tree type, tall grass/fern density, existence of vines, etc., should be picked sort-of-randomly but only within reason for the temperature and rainfall level - for instance, in a VERY hot (end-of-the-scale), wet biome, you could have either just oaks, just jungle trees, or a combination of the two. In a mid-temperature and rainfall level biome, you could have birches, birches and oaks, oaks, oaks and pines, or just pines.
Biomes such as deserts and swamps can stay the same, though, since they are "different" and should stay that way. If ground type and existence of mini-islands were randomized features, you'd get odd results. (same if the swamp grass color could be randomly selected. Ugh.)
Good work.