I think the sky is pretty fine as it is now. It's not unrealistic, it looks like what blue sky look like here in a springtime or summer late afternoon. Not all skies have to be hazy. Beautiful render and beautiful bulding. Did you model it yourself? I especially like the textures on it. In the top part especially, they show the right degree of weathering. Not too clean to be real, not too dirty to be a cared-for hotel. Also the composites of people and car are very nice. One thing I do not totally like is the building perspective lines. Although some "slanting" adds to the feel that this can be a photograph (with a lens distortion), there is a little too much of it for me.