Other than tectonic activity, what can reshape a world's surface?
Erosion is a powerful but slow and time consuming process that can make dramatic changes. The best example of this is the Grand Canyon. Carved by a river over at least 17 million years, 5000 to 10,000 feet deep, 277 miles long and 18 miles wide.
Erosion, whether it be due to wind, rain, water flow in rivers, glaciers is a major cause of geology, in the form of mineral grains, boulders and rocks to be mobilized and dispersed over a wide region.
Weathering is another force that reshapes the surface of the Earth. Australia is a perfect example of this. Weathering results in the physical breakdown of the of the surface geology due to weather, thermal stresses, frost, crystal formations and decomposition, oxidation, biological activity, alternating patterns of hydration and dehydration over a very prolonged period of time. The difference between erosion and weathering is erosion causes movement of material, weathering happens  in situ.
Fire tolerant plants such as eucalyptus and fire as a result of natural forms of ignition, such as  lightening  can change the botany of a large region, again see Australia. Eucalyptus has been described as a weedy tree that came to dominate a landscape when less fire tolerant plants became extinct.
Persistent fire or drought over a prolonged period can lead to permanent loss of flora resulting in desertification. Similarly, excessive rain due to climate change can lead to landslides and excessive erosion.