I remember seeing something about CDI.
It’s not even hard. It just requires an absurd amount of players that plain do not exist on some servers (particularly Devona’s Rest). It’s easy content that requires a lot of half-competent players.
Trouble arises when you don’t have a lot of half-competent players, either because your players are incompetent, or you don’t exactly have players.
I preferred the older content that scaled, where it’s possible for the best PvE players to solo, very difficult to duo, provided an ok challenge for a party, is optimal in a group of 10-20, and takes a longer time to complete when you have too many players. World boss timers are stupid; if you want to add more challenge just double the world boss’ damage output.