I've been use my D90 for landscapes with quite good results. At the beggining was with the 18-55, then i upgrade to the 16-85 with good results with both lenses. All that "matters" is the glass in front of the camera, and i think i may say that these kit lenses are quite good for landscapes shots. What settings are you using?
Nikonians!!! My best investment made after my camera!!!