The Nikon D500 is the long-awaited successor of the D300S, which I used prior to getting the D600. It came out in early 2016, and I have been using it for a while to take landscape pictures.
The first thing I look for in a DSLR is its dynamic range, the abillity for the camera to record both the shadows and highlights of an image. I think of this as more important than sharpness, because it affects the overall aesthetic of the image, and unlike sharpness, is something that will be detected even if you print it out. A camera with low dynamic range will have a lot of blown out highlights and pitch black shadows.
The advantage DX/Crop-Factor cameras is that they will be more effective for wildlife photography, while being far more problematic for wide-angle shots. They will need far wider lenses to compensate for the crop factor (like the Nikon 10-24mm or the Canon 12-24mm), which will not be compatible with a full frame camera in case you upgrade.