We'll be able to get high "levels" in disciplines. But will only be able to master a very few. It has been pointed at by the the team a couple times.
— The battle itself is closely related to the “Armory System,” in which you can change the classes (occupations) just by changing weapons or tools. In that case, I feel like I will want to try out different classes.
Tanaka: You may feel that way in the beginning, but it would be pretty hard to master all of them (laugh.)
— In that case, you could play just to master forging or cooking?
Tanaka: Yes, you could. But in the case that you need to go deep in dungeon, if you don’t want to fight, you may need somebody else’s help. Also, you could progress the adventure just by trying to master the fighting class, but you can’t continue fighting just with the same weapon because we have a concept of wearing out weapons in this version. So you need to strengthen it on the way.
— Does that mean you need the forging skill?
Tanaka: Yes. That’s why, if you want to do it yourself, you need to improve your forging skill, but it’s quite hard to master both skills, so you would ask for help from blacksmith players more often.
That last line is confusing. Is Tanaka stating the bold part in reference to forging and cooking? Or Mastering Fighting and Forging? It seems which ever one we'll be able to truly master few disciplines.
I'm guessing to be a master in something is going to be an extremely long road. Seems like high level disciplines will be the average for the character base. With 1-2 master disciplines dictating end game roles for a character (like merits in FFXI that dictate your worth in endgame in a job over another). You have the extra advantage that endgame requires. Just my 2 cents.
It might be possible to have more master roles. But it seems time will be a huge factor and how you use it to progress. The average player will have one or two. The hardcore players will expand to more master roles.
The seesaw effect to me limits a characters progress. It's the reasons why players had mules so they could max more then one craft out.