For me it's a mixture of the general homogenization of tanks, (IE: See how WAR and DRK are practically the same class but one has the best mitigation ability in the game) and the general removal of past systems. HW tanking was a much more complex dance between aggro, mitigation, and your DPS rotation. Some classes being more complex than others, like Dark Knight. The fact that tanking has been severely dumbed down and made more accessible - while this might sound petty - is part of why I don't really do it anymore. A lot of what made tanks fun to play was what drove DPS players from playing it.
