Since I hit the 200 S rank achievement so I thought I'd put together my thoughts on S rank conditions based on not believing anything I'd not been able to test out myself. There are still some I have no clue on. Anyways, since I don't get a lot of characters to work with here I put it on Lodestone instead. I note the ones where I'm uncertain on any of the theories when possible. Please note I'm happy to accept being wrong if your theory is something I can test myself somehow.

http://jp.finalfantasyxiv.com/lodest.../blog/1999706/