Coming from a Kotaku interview with FFXIV director, Naoki Yoshida...
I've said this on several occasions, but it hasn't changed. We would love for as many players to be on FFXIV as possible.

Conversations have been had with Mr. Phil Spencer of Microsoft, and the upper management teams of Nintendo. But I have proposed a condition every time I speak with any platform manufacturers. It's that the game has to have the capability of cross-platform play.

Of course with an MMORPG, once it launches and starts going into live services and operations, there will be a community. No matter how small it dwindles down to, we have to be responsible for taking care of those communities. It would become an obstacle if the first-party or manufacturer changed how patches are being implemented or online regulations. Some of our external parties' regulations don't have MMORPGs in mind in terms of how they're regulating their online activities. Those can become a hurdle when we consider operating FFXIV for an extended period of time, and so when I talk to those first-party companies, I ask them, 'Do you have the capability to prepare for that, do you have the resolve that you're going to make sure to take responsibility and take care of those, do you have that willingness"'
If we are able to come to some sort of agreement, a handshake so to speak, or if it does end up being that unfortunately we can't do a handshake with Final Fantasy XIV, ...