To be honest, I completely forgot they existed. I was working on their rep grind back in Burning Crusade, but it was terrible (as all BC rep grinds were) and I just lost interest in it when Wrath came out and there were all sorts of new cool mounts to get. The bar was half-way to exalted, but every time I looked at it (not very often) I imagined grinding that last 10,000 or so rep over the course of a week and I always, always came up with something better to do with my time.
Wrath faded to Cataclysm and the Netherwing were ever further from my mind. Rep grinds in the here and now had my attention, with more and better quests and generally a much less onerous feel to them. The Netherwing was the furthest thing from my mind.
Anyway, with patch 5.3 out I discovered that Netherspite now drops Netherwing eggs. And with that one little change, since I'm in Kara killing him almost weekly anyway, I suddenly found myself motivated to get that final bit of rep to exalted. I still hate the Netherwing quest, but at last, I'm exalted with the Netherwing and riding my new Azure Netherwing Drake (that's not him, it's just too cool a shot to not use). So here's my question for you: anything you forgot to do over the years?