People... People....
We need more zones first... The current jobs don't even have homes.
We're White mages with no church, monks with no monastery and Dragoons who can't even enter Ishgard.
the current jobs have no lore purpose. Define them first... give them a reason for being.
Yes, in real life we know they were added for more specific job roles, but in game... They just kind of... exist
Make people proud to be white mages... Make it MEAN something more than just "I have Regen."

Then, and only then, should we go about adding more classes/jobs
Seriously, A Samurai with no Daimyo (Which is technically a Ronin)... Ninja's who don't belong to any order and whose only purpose is to help kill Garuda?

I know you all want to have fun with new job types but if the current classes aren't developed more than just "X Class with a couple new abilities" then what's the point really?