So Why assume removal of Classes?

[lololink]

None of the story is dependent on classes, actually - nor even on the jobs. The story is focused around a set of NPCs and the adventurers.

Seems logic for a dragoon to learn at the lancer guild while the DRK will have a DRK master or guild, absolutely.

I think it's more like "Don't expect to see any new classes in the game once they add in Rogue".

Well they might add one if they find a good design idea, I wonder if with the class and job system they could do things like a RDM class that has 3 RDM jobs, one for each role.
(Soul crystals being then the memories of different ways of the RDM )