Depends ... In matter of Tieflings kids imortality its change of single value from 1 to 0 (or other way around, depending on how they implemented it )
But Larian is not the only one who can change things, i would gladly download any mod that will make all npcs killable. Since i simply dislike plot (or moral) armor and concider it butchery of immersion.
I didn’t mean they wouldn’t change because it would be difficult but rather because it would be gratuitous.
No doubt there will be mods which gives Larian another reason to leave as is.