I want to add my support for this being vanilla, the mod is so nice from what I have learned from my friends and seen ingame(haven't progressed through much yet myself though), and it appears to solve several gripes I have had, like with bloomeries and bee hives deleting resources into the void when destroyed. It doesn't simply remove that mechanic but gives you something to work towards to solve that which is nice in games to be able to work to solve a problem and feel proud when you do. It also is just satisfying when you level up. So I really think this should be vanilla, it improves the game in lots of ways. Probably with some tweaks as needed like others mentioned.