Check landscape work that you admire and you will find that most of the time the focal lengths used are the equivalent of a full frame camera with a 28mm to 45mm lens or greater than 150mm. The DX equivalent at the wide end is a 17-55mm f2.8 lens. I would rather shoot with this lens then carry around a 28mm, 35mm, 40/45mm prime lens.
Wider may seem better but wider also means reduced image magnification with objects in the frame shrinking and losing the impact that first caused you to decide to photograph a scene. Take any zoom lens that covers 17mm to 35mm (DX equivalent of 24-52mm) and take shots of a scene at 17, 24, 30, 35mm and compare the pictures on your monitor. You will discover the sweet spot for how you visualize landcapes and can then decide which lens will best provide the results you want.