Orrr, they are doing it again because the last one was a huge success. Even if it was only successful for a few years, they still made plenty of money from it. And a very large portion of the players have been asking for a new one for a long time.
I'm actually quite impressed with how seriously they are taking the new one. They are listening to player feedback, and running polls in game to find out which type of server players want. Hell, they are even doing a Beta of the new progression server so people can get a chance to report things that are out of place before the server opens up!