I don't see anything wrong in your screenshot, and I don't understand what you are referring to with "blotchy yellow blue textures". They are obviously the light rendered from the yellow vertical signs and taxilines blue lights and looks just fine.
The only things you can do to improve texture sharpness, is to be sure you set HD Textures in the Addon Manager at 2048 or 4096, and use Anisotropic filtering at 16x on your video card control panel.