Wah wah waaaaaah. Sorry, Alliance.
How would doing old raids at their intended level now a days compare to them being done when they were current content? Like if you got 40 people to lock their xp at 60, not take any DK's or Pallies for Horde, Shamans for alliance. Of course a lot of content got nerfed but with all the differing stat weights, changes in gear available(oh and no gear from next expansions etc...) and all the changes how different would you think it would be to do these things today?
Raids would be universally easier. New skills, talent trees, and just baseline coefficients for numbers and abilities have changed so dramatically from the days when these encounters were designed that players are just more powerful. It's by design, really -- the stronger you make your character naturally, the less reliant you are on gear accumulation during parts of the game where gear accumulation isn't the focus. Leveling, for instance, is about story, questing, and game play, not collecting loot. You barely need loot to level these days until you get to 80-85, when the curve gets steeper. Players are universally stronger, and running retro raids would be easier.