We should get the ability to select amplified and large biomes into a single world type or alouw us to select multiple types.
I love large biomes and i love amplified, i want to have both in my world but currently its impossible. Im sure alot of people feel the same way, and having the ability to choose more options is never a bad thing.
From a GUI point this could be achieved pretty much exactly like resource packs; A list of generation "modifiers" on the left, then you select the ones you want into a list on the right. You could maybe have their order in the list affect the priority, too (in case you want large biomes to take priority over amplified terrain).
From a coding perspective, this could probably get real messy/complicated real fast.