Later classes do get an XP boost to help with this problem. Whenever you're on a DoW or DoM class that's below the level of your highest DoW/DoM class, you get an extra 50% XP on any mobs you kill. Particularly if you can combine that with other XP bonuses (like my Free Company generally keeps the "Heat of Battle" action active, giving members extra XP) the early levels of new classes go pretty quick, not needing much more than the hunting log targets plus whatever FATES you run into on the way to finding those targets. As you get into middle or higher levels and the amount of XP needed to level up increases, it may become a bit more grindy, though.


[In case you're new enough to not recognize the acronyms yet:
DoW = Disciple of War
DoM = Disciple of Magic
in other words, these are the regular adventuring classes as opposed to the crafting or gathering classes, which are:
DoH = Disciple of the Hand (i.e. crafting)
DoL = Disciple of the Land (i.e. gathering)]