Slanesh, I don't care what you say. As long as their name is not exactly '' The Prophecy '' you have no right to tell them to change it. I agree that it would be rather confusing and above all unnecessary but that dosen't give you the right to play god.
It's up to you guys if you want to change it or not but it would be best if you just changed it.
And if you didn't know.. Prophet and Prophecy are 2 very different things so relax.