This will make me quite sad. There is no reason that a specific class should be required for a specific job. I can understand making the level of a job equal to the level of the class in order to prevent people from needing to level both jobs and classes. However they could simply have jobs be a title and the level based off of the current weapon. This seems like SE is taking a shortcut by squeezing jobs into the class system, which might be faster, but provides no benefits over a title system and a lot of consequences.

for a description of a title system. Titles/jobs are unlocked after a class has reached a certain level. It can then be assigned in addition to your current class/weapon, thereby restricting skill equipable but providing other benefits and abilities. people can then look at the combined job/weapon to determine expected party roles.