Full text here:
http://www.1up.com/news/final-fantasy-xiv-ps3-delay

The short version is:
> "The main reason was the memory," he said through his translator. "On the PC, they have enormous memory. For PS3, there's a restriction. They are adjusting the memory size and customizing it; it took longer than we were expecting. But we're really working hard to bring it out as soon as possible."

inb4… wait, too late. PS3 limitations.