I wold a option to allow blacklist worldgen in specefic biomes.
Adding a blacklist in the worldgen type ( example tin, copper etc ) that a pack maker can use wold be realy helpful for packs that want to limit the worldgen / matrials is generated in the world and make it harder to find X type of matrials.

Also a option for marble is to allow to set Max y and min Y of the worldgen.

I like the idea of making marble more configurable. Whitelisting/blacklisting worldgen in specific biomes... It'd be a nice addition, but I think it'd fit better as a completely separate mod that just allows you to customize worldgen. I'd like to know what the rest of the team thinks about this :)