To elaborate, i'm aware of the fact that Xur has always sold engrams and now he is selling a way to get those engrams in the wild. In actuality, it would be another step between the player and the loot, thereby evening it out. What clearly happened instead however was that people were able to get a ton of different engrams in a short amount of time. Sure it may take longer, but it wouldn't be much different than Xur selling an engram for every weapon and armor slot.
I'd just remove Three of Coins from Xur's inventory and have it be a quest reward, possibly even rewarded by him every weekend.
Maybe it's just me. If Exotics aren't overpowered like Gjallarhorn then they shouldn't be such a rare sighting, especially now that Raid Gear is more coveted than the Exotics. On the flip side of that, it bothers me that they were so easy to obtain. It kills Xur, it kills the replayability, and it kills the bell curve availability of the items.
It's essentially "Cheese Atheon for Mythoclast" all over again.