If the worry that leveling is going to be too long easy alternative methods could be implemented. Things such as experience materia could be added to quicken but not destroy the leveling process, this along with experience boost gear sets would be a far easier solution than just smashing the lovingly crafted story to bits.
Another idea could be to implement low level quest packs, giving players the ability to level alternative jobs and classes through side quests (A quest chain in the vein of Hildbrand with a decent amount of experience and experience items attached). This would be a far nicer way to flesh out the game at lower levels, incense players to return to old content and if you really must, make some money on the side if you really must sell something… (Yes I know development cost is expensive).
I would be deeply disappointed and disheartened if this idea is given the green light for a worldwide roll out.