the seated man makes a good focal point for the photo, however the impact is lost becos of the background, e.g. his head "merges" with the background. i also feel that the composition is a bit too tight here, so that the top of the building is cut off. i think the use of a wider angle lens might help here, together with trying out other angles to photograph the man. moving a few steps to the side would help to isolate the man better from the background, and also get a glimpse of his face.