I don't really see why the Inca shouldn't see sheep, I mean there were no horses or cattle anywhere in the Americas, should all america-based civs just not see any pasture-resources because of that?
This mapscript thing affects one situation and one situation alone, when a sheep spawns on a hill next to multiple mountains, and yes that does happen a lot, mainly because mountains don't have any food on them. But it's honestly not like there are more mountain-hills with sheep on them than without sheep on them. This whole discussion just feels a lot like 'game is conspiring against me'-syndrome, confirmation-bias and straight up over exaggerations.
Let's figure out a way to make the terrace-farms that you actually get to build feel cool and rewarding rather than upsetting the pasture-balance, and making ridiculously ugly terrace-sheep tiles that in the end won't really change anything.
I agree with Funak. Not giving sheep to the Inca sounds like a very inelegant solution. The last two times I played the Inca I used Tectonics & Planet Simulator and both maps were perfectly playable. Is it just the Communitas map that overfills hills with sheep?
What will the map look like from the Inca player perspective? Will they see pastures in enemy land but without visible resource inside? What happens if they conquer that city, will the sheep disappear so they can build a terrace farm?