This idea has always intrigued me, we often see amazing concept art but outside of 2D games it's rarely fully adopted, Team Fortress 2 and Okami being among the few. What I would like to see is games like Guild Wars 2 to fully embrace the amazing art that has been shown, imagine dragons made out of brush strokes, characters with a handmade look and vistas all around you that make you 'print screen' perhaps a bit too much. Straight up cell shading doesn't do it for me, somehow it looks too sharp, not free form enough and I don't like the thick black lines everywhere. So am I asking too much? would having a game like Guild Wars 2 looking as close to it's concept art as possible be too high a graphical jump at the moment?
btw I think Guild Wars 2 is a good looking game all round perhaps isn't the best candidate for this kind of visual treatment, it's just it's concept art is so good I would have loved for the full game to look as much like it as possible.