I can't think of any particularly rationally valid reasoning to not bring the hard won HoW exotic weapons forward to year 2. Can you?
Honestly I'm pvp trash, the Queen Breaker's is my pvp weapon of choice and the only one I can begin to compete with in ToO. I'm missing it sorely.
I don't think anyone would call dreg's promise, lord of wolves or queen breaker's broken or OP sooo... some of the few earned exotic weapons in Destiny were only really usable for a couple (what was it? 2 months? ) of months before TTK hit.
We've got some not-game breaking exotic weapons we got a limited amount of time with. I think it's time to bring them forward to year 2.