The reason they did this is because getting weapon drops from master vog is actually worse than armor drops, since the weapons are the exact same as what you could get from normal, and the armor is actually different in that it is guaranteed to have stat spikes. They also made it so that, other than pinnacle power loot, you arent locked out from either for doing the other one, so if you care for the weapons you can go back and run normal vog, but if you're the kind of person running master vog I dont see why you care about regular weapons anyways when you will realistically get more value from the timelosts.