Personally I'd recommend playing it now. Partially because I think the game only gets better with every subsequent playthrough, partially because it'll probably still take quite a while until it's actually released. There was a rumor that it'll be June but I think it'll take some more time than that. So yeah, you might end up waiting a lot longer than you had anticipated.
for what it's worth, if you follow the pre-order link on finalfantasyxhd.com, Amazon lists a release date of Dec 31, but I'm not sure if that's just a placeholder.
Pray to Yu Yevon. Dream, fayth. Forever and ever, grant us prosperity.