Weather would indeed be a good addition.
Bast emitted a positive opinion about this already (
here) but the thread wasn't as detailed as this one.
I have nothing more to say about these 4 natural disasters they are good and planet-specific. I would add the cyclone on planets with high atmosphere. The electromagnetic storm should happen on planets with weak magnetic field. Maybe asteroid-like "planets".
I think the different biomes and planet types need to be figured out first, before making further plans on weather.