One thing I did not see anyone talk about is <experience point>.

Now one job can be unlocked from a class. Both class and job share the <same experience point bar>. If more jobs were to branch out from the same base class, where would the <experience point> that you get go to?

Sharing the same 50lvl abilities from the base class with another job is boring and basically make the two jobs the same. And your new job would immediately be lvl50 after just finishing the unlock quest of you have already had the base class leveled to 50, which is something I would not want to have.

I am wondering how they are going to implement this [one class -> multiple jobs] system, if that's what they intend to do.

My guess is every new job would require a new base class to be added.