Hi,
you have multiple "issues" at once that cause this blurriness. To name a few:
1 - very strange setting in the atmosphere. Try to use the default atmo in comparison to spot all the differences
2 - increased GI to 1.5 on surfaces. This is particularly problematic with the sea, reflecting a whole lot of sky blue onto the terrain
3 - very "soft" colors for the terrain, and quite uniform and dark at the same time.
4 - maybe also the sun is almost vertical, casting very little shadows, hnce the terrain features don't appear very much differentiated.
If you change these you'll see a big difference, I bet :-)
Regards,
Frank