You can read this about how much of the world is loaded (and can be affected by one spell) currently: https://wizardsofthecode.itch.io/soulash/devlog/84828/consistent-world-of-soulash
I'm not gonna say no to world changing spells, but there is a lot to think about how to deal with these. Discussion and ideas are welcome, but it's not going to be possible before v0.5 at least.