I mean as FFXIV ramps up in popularity and scale, they could be growing their team and thus push out faster expansions. Moreover, their team is getting better at understanding their own game and how to build systems and flesh out content more rapidly. That said, March still seems way too soon. May would be believable but considering how these things go, we haven't even gotten a title or a trailer, let alone interviews and decriptions of content, etc. They'd want to build hype far longer than just 4-5 months, especially since Fanfest lasts for about 3 months as they tour to NA, Europe, and Japan.