I think a map marker function is downright needed. The sheer size of the world(and fact that they are so much zones as....well.... REALLY MASSIVE ZONES!!!) means having the ability to mark pretty much anything is desperately needed. For example if you find a interesting place you may want to mark it. If you find a particular camp for a certain mob you may want to mark it. If you find a great gathering area and would like to mark the kind of trees there are there. I mean the uses are endless.