The texture resolution is depending on the HD texture settings in the Addon Manager and, since JFK V2 uses 4096x4096 textures size, anything below that will reduce the quality compared to how the scenery has been designed.
If you are already at the maximum resolution, and you still have runway textures blurred, it's due to the fact you haven't enabled Anisotropic filter on your video card control panel. Use 8x or 16x and select the option to "enhance" the application settings. Every scenery that uses custom runway textures needs Anisotropic filtering to be enabled on the video card.
