Not as easy as it seems at first blush.

Quote Originally Posted by Zenoxio View Post
The PS4 has been announced and has PC architecture
But not a PC operating system. The Xbox 360 was easy for them because it pretty much runs DirectX natively. A native PS4 port would need to be retooled and recompiled for the custom PS4 firmware.

as well as Gaikai integration to play previous generation games
You missed the important word "eventually." Out of the gate, the PS4 won't even play your PSOne Classics.

Since XIV will all but assuredly be ported to the PS4, we probably have a better chance of XI being ported to the ARR engine (which was built from the ground up with multi-platform capabilities in mind) than a custom port of PS2-centric XI to the PS4 as-is.