You can count of one finger the number of mechanics 95% of Classic raid bosses have a piece. The content isn’t hard. It never really was, we were just a different breed of players back in the games infancy.
As it stands right now with SoD power creep, if they do nothing to the end-game raids, all of it will be PuGable in a group of 20 people anyways. Some classes are already pumping out Level 60 pre-BiS numbers. Lol.