I wonder ...
Do you think its a bug that Druids are able to use metalic armor without any penalisation? Or do you expect them to change it?
I fully expect them to change it/fix it eventually. Right around the time they implement limitations on what spells wizards can learn haha!
because you are 100% right, they CAN wear Medium armor, but they are not supposed to be able to wear metal. Hopefully there are some options for alternative material druid armors.