I understand why there are map chat restrictions. However, I think these should be relaxed for active commanders in a WvW map. People with commander tags need to be able to give orders in map chat and let others who may not be in a mumble/TS/Vent server know what the plan of action is. Otherwise the zerg will just scatter on available targets.
I was following a commander that I happened to be on a voice server with and they had to delegate someone to chat each time because their map orders were being supressed due to usage limitations. There should be some additional messages allowed for folks with active commander tags to prevent this. Just my 2c.