With a spare couple of hours, I decided to lead a small retro raid through Hyjal (Archimonde being the only BC end boss besides Sunwell that I hadn't killed).
- Ignored NPCs for the most part (tried to involve Jaina/Thrall for bosses where possible)
- 10-13 people - a few sub-80s, including the OT, 2-3 healers
- 1 shot everything except Archimonde, even with quite a few who had never seen Hyjal before
- Archimonde took a few goes, but went down fairly quickly, even with a couple of deaths towards the end of the fight
It was surprisingly easy; I have no doubt you could do it with less than 10 people, if they were well geared and knew the fights (particularly Archimonde). 15+ level 80s would blitz the place.
After the success of last night, I'm keen to try BT (I still need rep) and Sunwell (for Thori'dal) too, although I'd be wary leading a raid through the latter - I'm not the best raid leader and I tend not to volunteer to lead raids unless I know the place fairly well.
However, it's rare that the guild officers will initiate retro raids (they're probably burned out from leading our normal raids, which is fair enough!), so if I want my legendary bow I'll probably have to bite the bullet (arrow?) and lead the raid myself.