I don't shoot this lens very often any more as I tend to shoot either with my full-frame Nikon D800 or the micro-four-thirds format Panasonic GX7. When I shoot with my old Nikon D90, it is the lens I will use most often. If used properly, it gives better results than the Nikkor 18-200mm lens that my wife uses all the time. It works quite well. These shots were taken with the 18-55mm lens.
It seems to me that you should concentrate on using the tools that you have and get the most out of them before investing in a new lens. If you find you are limited by some characteristic of the lens, then invest in something that will help overcome the shortcomings of that lens. If you want to shoot landscapes, the first thing I would suggest you invest in is a decent quality tripod. I suspect that will help you get better pictures, far more than getting a new lens.