Something for the future - replace standard fog with actual atmospheric scattering. Of course there's no need to do it per pixel. Some low res background texture where fog color and density will be sampled from will do just fine. Uniform fog will never look good. It's a relic of the past nowadays. Video below shows how weird changes in fog density when you're rotating camera. And of course fog color doesn't match sky color which is another dead give away. Sky color can vary from left to right edge of screen and fog should be able to match it.