Being able to define different noise settings per layer of blocks within a noise palette would be very handy - lets say you wanted the top layer of blocks to be organized by blobs of cellular noise, then the layer below that to be a static arrangement of blocks. This wouldn't be possible with the current config options (you could do it with absolute noise but that doesn't factor in terrain shape).

Could be configured simply like so:

layers:
  - materials:
      - "minecraft:ice": 1
    noise:
      noise-stuff
    layers: 1
  - materials:
      - "minecraft:water": 1
    noise:
      noise-stuff
    layers: 1

I will likely implement something similar to the example, where the noise key (which will probably be called distribution) is optional, and if it is not present, the layer uses the noise function defined in the root.

Implemented in 20de531