I don't personally think it should be, nor should Rhok'delar.
I think more things in WoW should have their day, then fade away into the sunset, becoming more rare as those who have them quit or stop displaying them. A new quest equally challenging shouldn't result in another Benediction, but a new item.
One of the things I do miss from EverQuest was the stories of events and things gone by. While they were gone and no longer obtainable, there was always something to come in the future that would be cool for those who only heard stories of items/events from the past from those who were there. It added a bit of history and "legend" to the world.
I'm not a supporter that anyone who's ever played WoW should have access to everything that's ever been in WoW.