Rohan from Blessing of Kings has a very interesting question on his blog, which relates to my previous post: Was Blackwing Lair boring? He was watching a raid video of Blackwing Lair and noticed that it seems a lot less dynamic, with people moving a lot less than in current raids. Thus as a "spectator sport", old school raiding certainly was more boring than modern raiding.
But I was in Blackwing Lair, even got up to the end boss Nefarian, and it wasn't boring at all. And the difference lies in what I described in my previous post as the difference between learning to play your class, and learning to react to specific encounter events. If you read old strategy discussion on Blackwing Lair you will encounter concepts that are foreign to modern raiding: mana efficiency, downranking spells, healing rotations. The very idea that you would have to set up a healing rotation, in which one healer is healing, while the other is standing still to regenerate mana during the fight, is completely unknown to somebody who only knows today's raids.
This is actually one reason why I don't raid regularly any more. I'm in the somewhat curious situation that I find raiding both "too easy" AND "too stressful". Overall it is certainly challenging, but the challenge often lies not in playing your class well, but in reacting quickly to various events. There are no choices to make, no decisions to take. You get a message (which you can make more obvious with addons like Deadly Boss Mods) that event X is happening, and you need to press button Y inside of Z seconds to counter that effect. "Boss casts buff on himself. Dispel!". "Boss casts fire spot on you. Move away!". "Boss makes everybody deal damage to his neighbors. Stand at a distance to everyone!"
In Blackwing Lair I wasn't running around so much. There were a lot less scripted events for which I knew that when they happened I had to push a specific button fast enough. In Blackwing Lair I was actually still busy playing my healer. I had to watch health bars and make a decision of whether to cast a fast heal which wasted a lot of mana, or a more mana efficient slow heal. If I would make the wrong decision, either somebody died because I casted too slow heals, or we wiped because the healers had cast too many fast heals and ran out of mana before the boss was down. Or as my favorite Sid Meier quote says: "A game is a series of interesting decisions.": Having to decide what spell to cast and that decision making a difference is interesting and thus fun. Having to move out of the fire is *not* an interesting decision, only your reflexes are tested. I find "we wiped because I moved half a second late" frustrating (especially if that half second was caused by lag). I find "we wiped because I made the wrong decision which spell to cast" much more motivating to go back and try again. Only decision making is a process which is hard to capture on video, while moving out of the fire is more visibly dynamic.