While the job names are the same as ffxi, they are also the names of jobs in other ff games as well, this is a ff game which is why they went for the old job names.

For example, in FFIV Kain is a Dragoon and in the story Cecil becomes a Paladin, in FFI you can have the jobs Warrior, White Mage, Black Mage, Monk and Red Mage (I know some of these arent in use here yet) in FFV there are aload of jobs including White Mage, Warrior and Monk, they arent copying FFXI, they are keeping the traditional jobs alive