It may just have been because I had never done it or even tried it on heroic before (I did not start playing again til october really) but we recently went in and did all of heroic BoT for a dragonslayer sell, and I can honestly say that the council was by far the hardest raid boss I have seen this expansion. Even heroic spine was nowhere near this pre-nerf! If we did not over-gear it like crazy, I do not think we would have even killed it to be honest.
Am I just blowing it out of proportion because I had never even seen a video of the fight before and was not sure what to expect? I got the gravity crush thing both times, so healing was just crazy (I was on my holy paladin main) We did one shot it, but every single person in the raid but the one we were selling it to was 403ilvl+, which as you know is quite a bit higher then the loot it even drops.
Pre-nerf rag was quite difficult as well I hear (I was not there for the guilds kill, as I was not raiding yet at that point) so that may beat it out :P