How do we make the game HARDER?

I was wondering about what the game needs to be HARDER.

- Blood Types: Complicates blood transfutions and Organ harvesting.

- More diseases (Tuberculosis, ETS, Leprosy, etc)

- Ecology affected by your faction actions and other factions, so Polution, mods already give you some events like Ice Age, and the base game with the Toxic rain, but Im talking about something that could permanently fuck up the planet, like an ecologic collapse, and you slowly see how plant life, animals go extint and the oceans and rivers go dead.