Finding diamond make the progression in early game quite easier.
I think it would be interesting to make crafting some item that requier diamond to use something similar to the diamond ingot of btw et bwm.
https://sargunster.com/btw/index.php?title=Diamond_Ingot
This combined with ore block or chunk replacing ingot in chest and loot would make the progression more linear.

Maybe a diamond/gem cutting feature? Divergent Underground has a feature where mined gemstones like diamonds/emeralds or the BoP gems drop from the ore as a raw gemstone and needs to be "cut" with a chisel in a crafting recipe to become their regular item (thus becoming usable in their usual manner).
Instead of a crafting grid recipe, how about something like a hammer recipe on an ironclad anvil with a chisel item in the offhand? It would give some requirements to the usage of diamonds, but more immersive and intensive than just a crafting recipe gated by just the chisel would be.

I agree and I'm going to look into this in the future.