Thinking more on this in terms of people wanting to preserve the tradition, but also making this more palatable (as well as thinking about space concerns) I wonder if people would find this change acceptable.
Armor: Light armor, medium armor, shields (druids traditionally will not wear armor or use shields made of metal)
I think this A) highlights it being a choice and B) still gives hooks for those people who want to follow tradition. And it is a single word, which shouldn't ruin space concerns.