There is also the development side for reasons for putting in things like the echo to make older content easier for people that didn't clear it when it first came out. I remember that in Warcraft such a small percentage of the population even saw the last boss in I think it was Black Temple, that it made some of them mad. They put in a lot of time and money to design that, and they want people to be able to see and experience it, so with Wrath, they lowered the raid size to make raiding more accessible and with ICC put in the stacking buff for the older floors so that more people could get in on it.