If they can manage to keep the pace moving via quests and other story related content it probably wont be that bad. Thinking back to older ff games getting to x place in the story generally takes a set amount of time and you generally arrive there at about x level. Assuming of course that you did not do extra grinding or rushed.
How ever I am of the opinion that the 30 hour's for level 15 is a wee bit overboard or hopefully just a bit hyperbolic.
