That's not entirely true because when I did my first completion last night I got helmets twice. Honestly they should just have a traditional dungeon loot system like they have always had one encounter gives you a weapon or piece of armor and then so on so on so on. Just like with crota's end when you did the bridge you always knew that you would either get the pulse rifle or the boots or the shotgun whatever it was but you always knew what you were getting it wasn't a damn guessing game