Yes the shadows do look fine to me and the image is a simple but stunning composition. The horizon in the centre of the crop works well but wonder if a little more contrast in the clouds would give little darker view.
One thing that does get me eye when I look at the image is the horizon on the right hand side ? Not sure what it is but it looks like the start of an island as it is a little raised on the horizon. With the image having just the two subjects it distracts your attention away from them.
If you crop it out this image would be a stunning one that would look great in any gallery
Really like your editing skills