I like your over all look. I'm not such an expert myself, but since no one else has commented. I like you stippling for desert. I see two dune symbols/brushes and I think they both look very good. My only suggestion would be to use more of them in a pattern to look more like dune wave patterns. perhaps. just one dune in isolation can be mistaken for a hill I think. The settlement symbols are a good choice. But the thin clean lines on those symbols look a little too clean for your map style. You might want to blur them just a little, maybe widen the lines a pixel and otherwise muss up a bit. I'm not sure how but they don't look hand drawn as they are.
map style looks great. coast lines look great.