Almost no class completely changes going from a "class" to a job, a conj is a WHM at level1, a pug is a MONK at level1, and a arcanist is a SMN at level1. The jobs all play exactly like the class that came before it, with maybe 5 new skills that don't completely change your playstyle or role. Scholar is the only job in the game that uses the job system correctly and is actually fun/interesting and unique.
