That would be shooting themselves in the foot, considering there might still be plans to put FF14 on 360. Though if the PC base eventually recovers, that might be a different story.
I'm not sure how much work it takes to do those DX 9/10/11 grafts that mult-platforms do. Definitely not worth it if they are planning to retire the engine from the winPC field.
Something like OpenGL for instance would be the path if they eye the iphone/pad/mobile market which has been seeing massive growth and is touted to be the unofficial 4th-console.