It would highly depend on what the combat system in the new game was like (at this point I'd expect a more hack 'n slash style combat, which doesn't appeal to me in MMOs) and if it did away with any thing I dislike about XIV.
Also as much as I get fun out of XIV, if this new game was also designed with the "progress is done solo 90% of the time" mindset I'd probably just stick with XIV until I was done playing MMORPGs.
