MMO's changed forever for me when I discovered the RP realms in Warcraft. It was there I got to experience player made events where people took the basic world and story of the game and expanded on it to make it something more personal. A lot of mmo's have role playing servers because there are quite a lot of people like me that enjoy roleplay.

Even in this game people have created unofficial rp realms. It's no coincidence those servers (Balmung and Gilgamesh) are at max capacity most times. An official RP realm would not only do a bit in alleviating some of the stress of those servers, but also serve as a beacon for newcomers who are looking for others to role play with.