Hey there.

You are indeed achieving a good balance in terms of color (in my humble opinion, that is) and your continents are increasingly realistic. But, you will soon, if you haven't yet, hit a wall... That's how much you can do with Wilbur. Wilbur works wonders and it is truly an achievement for mankind (at least, the part of mankind that does fictional mapping as a hobby), but it works well only for regional to local sized maps.

This is because it lacks some important aspects of the erosion process - mainly sediment deposition and variations in rock hardness. That's why Wilbur will never give you meanders, swamps and deltas, nor lakes and waterfalls.

I have tried to use Wilbur for continental maps, just like you are using, and I got a bit frustrated about it. But if I had the time/energy, here are some things I would do if I was to go back at using it at this scale:
- create "rain" maps and use them as masks when applying erosion
- create "icy/snowy/glacier" maps and use them as masks for some very deep erosion
- create "rock hardness" maps and use them as masks to apply random "up" noise
- create "lowlands" maps and use them to apply a smoothing "add" operation of a few meters every rain cycle
- create "desert wind-drive erosion" maps and use them as masks to apply a smooth/flatten effect like the actual effect of the wind on dry regions

All these and a tremendous number of very-light-on-their-effect cycles could probably turn results like yours (impressive at first sight, but quite repetitive when it comes to features on a continent) into something closer to reality.

In the meanwhile, something simpler you can do is simply to add more geological features to your continents - strings of mountain chains (small and large), plateaus (normally, one side of a mountain range is higher than the other, and very commonly, a plateau) - and to put some more effort in respecting general climate tendencies (river based erosion is hardly noticeable in the tropical desert areas, closer to poles you will have mountains eroded almost to sea level in channels, because of the glaciers).

Having said all this, I hope I didn't come out too negative. I appreciate your effort and am genuinely interested in where it will lead to. Keep it up!