The contours might read better at a higher resolution. At this size, they just turn into mush. Likewise, the political coloring might look better at a larger size—if this were a poster map, for instance.

And combining topographic and political maps into the same image may also hinder understanding. What is the purpose of the map? Who uses it, and what information do they need when they do so? Perhaps you could split the data onto two simpler maps.