The magic system as well as adding some of the more recent armors was done exactly to address that.

Players that need the metal armour have choice to use it, but the more useful armors still leave you open to taking bigger hits from mobs of earlier biomes.

I do agree thou, would like the diminishing returns on be a little more aggresive so that we actually take damage from Black Forest mobs in later armors... but then they die fast anyways, and with the health from late game food you can fight hordes of them naked without dodging/blocking and they still cant make a dent through your regen. So "fixing" armor would not change a thing.

In these kind of games, its either or: get meaningful progression or have meaningful fights in early biomes. Which is fine IMHO, we dont need every game to tick all the boxes, especially when they are mutually exclusive.