Late-Expansion Thunderfury Owners (those who farmed it after vanilla)
Did you skip straight to the bosses you needed? In Cata I was soloing the whole thing until Garr dropped his first binding for me, since then I've been skipping straight to Baron Geddon every week with no drop of the other half. Could this be because I'm not killing all the bosses or am I just being paranoid and unlucky?
Just being unlucky, but you might as well kill the others for the battle pets and to spawn ragnaros for the eye of sulfuras. Also, if you are a miner, you need something like 400 dark iron ore. Mostly found on the walls in MC.