I don't think MS has got anything to do with the FF11 servers, so I'm not sure what they would be thinking of doing to them.

SE has got planned content for at least another year (this info was released in january or february this year), and FF14 is scheduled to be released this year as well, which means a definite overlap if things go as they plan. I also think it's a pretty bad idea to shut down the game immediately after they release the last bit of content, because then people won't even be able to finish it before it's too late, and the development of said content would have been a waste of money for SE.