Some interesting/awkward results, woodb3kmaster, but the issue with your maps (to me) remains the linear ridges. Ridges are formed when continents collide, or when oceanic plates subduct under continental plates - I'm sure you get simple tectonics, since you've taken the task of creating an earth-like planet. But, there's one thing about those ridges - they are created by thousands and thousands of eathquakes, over millions of years, and not all earthquakes happen exactly in the same spot. This results that erosion happens at the same time the rising is happening, and while some areas rise, others sink, even if only slightly.
Have a look at both these pages about recent earthquakes:
Nepal's 2015 Earthquake
Italy's last October series of earthquakes

As you can see, there's localized sinking and rising. If you want to create a ridge for Wilbur to erode, and make it look realistic, then you need to "simulate" a bunch of these events. Perhaps with a very light brush over the black&white map, small strokes repeatedly, more or less in the same direction, across the area you want to become a ridge. Only afterwards take it Wilbur.
Prefereably, still, interchange "eroding" and "quaking"