I think the hardest difficulty should be where the game only saves when you quit the game or go back to the main menu. And it should always save when you do that. And all of those saves should overwrite one another.
So you basically only have one save. A real ironman mode. No save scumming allowed.
And no revivify scrolls. And no Withers. A real permadeath situation.
And no fast travel. And you can only camp when you touch a waypoint.
And no magic pockets. What you have on you is what you have. You need to spread the consumables around beforehand if you want to use them in combat.
