The fact that you admit that you have “Druids running around as Rogues”, the phrasing of it, that it is a class running around with a look that does not belong to that class, if anything strengthens the need for mog-locking. Druids should look like Druids. Rogues should look like Rogues. Venthyr should look like Venthyr. It has gone too far and a change needs to be made.
Time to draw a line in the sand.