One thing I love about this mod (and wish was more present in the base game): multiple ways to get the same resource
One of the things Realms of Exether has instantly captured me with is how different playing in different places feels, not through railroading via journal entries, but completely organically thanks to how diverse the production chains are.
In one playthrough you grow your dyes together with your fabric on Sunweave plantations while the main source of iron for your whole industry are Rustail fisheries; and in a different one you get your dyes from squids, who are also now providing the monster essence for your potions. This thing alone makes the game feel so much more immersive!
The base game is so limited in this regard. I think it would've been so much better if it took some lessons from this mod and added more variety. Even something as little as splitting logging into boreal, temperate, and tropical with different softwood/hardwood outputs could've been nice.