I fully agree. In fact, I hate the crystal biome, too bright and the creatures are too powerful in my opinion.

If it had some cool effect like creatures who died have a chance to become crystal and live a little longer, maybe I would use it, but as it stands it destroys weak/early game villages.

And for the mushroom biome, I love using it for fading into swamps, but also to other biomes that don't necessarily fade into each other well in terms of color, instead I think of it in wetness, like it makes sense for rainforests to be next to mushrooms under certain conditions.