Well, the point I was trying to make and I kind of agree with GM4Him, is that with a little imagination, yes, you can have medium armors that are not made of metal. Perhaps they need to be specially made (hint, hint, HINT!!!! Crafting! :D)
Crafting, yes. Not sure if it's still allowed in 5e, but here are some examples from old games based on previous editions:
- In BG2, you could craft an Ankheg Plate armour, which was an equivalent of Plate Mail +1. Good option for early game, when magical armours are still unavailable.
- In IWD2, you could commission 3 different armour types made from Boring Beetle shells (I believe it was Boring Beetle, but I might be mistaken), 1 medium and 2 heavy ones.
- In NWN2, which is a veritable crafting paradise of all DnD CRPGs I've seen, you had the following options, apart from basic Leather:
- Salamander Hide: +1 AC, Fire Resist 10/-, 40% weight reduction. Suitable for Leather, Studded Leather and Hide armours;
- Umber Hulk Hide: +2 AC, Mind spells immunity, Half Plate, Breastplate and Shields. This is technically a metal equivalent, so you craft any plate-based armour as you would normally do, but use shell pieces instead of metal;
- Wyvern Hide: +2 AC, +4 Poison saves, 20% weight reduction, Scalemail, Breastplate, Half Plate, Full Plate;
- Red Dragon Hide: +3 AC, Fire Resist 20/-, 20% weight reduction, Scalemail, Breastplate, Half Plate.
Some of these stats don't make sense in 5e anymore, but hey, considering how frivolous Larian has been with implementing 5e so far, nothing should be off the table. It's all up to them (or the modders, if we're lucky, but Lucky is still broken afaik).
Regarding using metals in general, I think it's reasonable for Druids to shun iron and steel, as products of civilisation. However, even Druids should recognise the potential of cold iron and alchemical silver (I don't know, do we still have them in 5e?). Especially considering the nature of some of our "allies"...
