From the top of my head I'd say xavi is the obvious answer here. But just some food for thought, a couple of years ago, when oliver kahn retired, everyone was expecting him to become a coach, and instead he went to college. when people were asking him about that, he basically said that he has spent 20 years playing football and that life has so many other interesting things he wants to experience as well. Most of our guys seem to be rather sophisticated and I don't think they would be at loss in the civilian world. I can easily picture iniesta becoming a winemaker, you know, floating through the vineyard with 50 grapes at each foot.
But yeah, in the end if he wants to xavi would probably be a very good coach. I'd like to see him one day