All of Draztal's points about attunements are valid. I salute you, brave EU CM, for your willingness to say what so many people seem to have forgotten about them. They're content barriers. That's all that they are. The people remembering them so fondly are, so far as I can tell, drunk out of their minds on the sweet and heady wine of nostalgia or just really invested in creating artificial ways to keep other players from seeing the content. I don't understand the mindset that demands extra hoops outside of the content and its actual difficulty be added to arrest progress.
I like a challenge. I do hard content in my raids. That's fun for me. What I don't like or want is a barrier to entry that has nothing to do with skill, just time and the ability to get other people to help me get through a series of stages that serve no other purpose but to delay me, especially when we're already delayed by other aspects of the game anyway.