Custom World Generation (Non-Superflat)

The custom world generation feature would allow for better classic world type (Non-superflat) customization by allowing the player to toggle EVERY specific biome on or off. For example: let's say I want a tiaga only world, I would toggle every other biome that isnt a tiaga off and after creating the world, I could explore infinite lengths of Tiaga. And maybe there are some biomes you just really hate too, you can toggle the ones you hate off and not have to worry about them ever again. However this world feature may be considered a cheat and will most likely turn off your abilty to receieve trophies/achievements in your world.