FFXI installed completely to disk on both PS2 and Xbox360. The onlything run from the Game Disc was the POL Executable link for the Xbox360. Once the game was installed on the PS2 though you didn't even need the CD in to start the game. (The biggest flaw in the 360 version is requiring the disk be in to play.)
Also they announced that the currently missing genders will be attempted to be ready for the PS3 release.
Also you can install the PS2 client for XI onto the PS3 if you have a backwards compatible system, enough hard drive space, and you download the hard drive configuration tool from PSN.