Know what is useless? Your Class.

[Zourin]

Classes are not supposed to be used over jobs.

Think of it as this. Your class is the base and your job is the specification of that class. It's kind of hard to see it that way because every class so far only has 1 specification. for example:

A Archer has the jobs: Bard, Ranger, Hunter and Sniper.
A Marauder has the jobs: Fighter, Dark Knight, Warrior, and Soldier.

This game is supposed to have a lot of jobs, I think Yoshi said at one point, he wants all the jobs from Tactics advance into ARR.

What's the point of a specialization if there is only a linear progression of your existing class? The only class with specializations is the Arcanist.