I've done a lot of fussing with this over the years, and quite frankly it comes down to how well your card does filtering. (bilinear,trilinear,anisotropic)
Unfortunately I have an All in One with a crappy Intel card who's drivers won't perform anisotropic in FS9 even when forced through the driver
So I have to settle. If I move my MIP quality to 4 with Triliniear set, I get a blurry mess in urban areas. if I move Mip to 5 or 6, the roads and textures have more pop, but I have to deal with shimmering. I use FSUIPC to limit visibility to 40NM, the "haze" seems to cut down on the shimmering.
So I set MIP to 5, visibility to 40 miles and deal.
I would check your filtering settings and MIP level settings. I think you will find some improvement on the blurries, but you may have to deal with some shimmering.