How about a potion or boost that ONLY works when you've completed every single story quest to date and have at least 1 of each class type at max level, like for mentoring. That way noobs have to progress as normal and those who are lazy can boost the classes they don't want to dungeon or fate grind on... TBH, if I could boost all my tank classes to 60 I would, I hate tanking but I want all classes at 60. :P