Perhaps you could set the atmo density a bit smaller, so the haze is not as intense. It is a huge area, and prone to hazyness, unless you have something dark (trees, rocks) close-up in front.
Or set haze very low and introduce a low soft and small density v2 cloud for haze, which you can mask by a distance shader, so not to have too much haze in front.
You can also experiment with the tonemap possibilities in the render tab, say raise contrast.
