I mean, Petra dosen't really look great with all of these dirt houses... or at least the top halves of them... maybe changing them all into spruce planks would look better? Dirt looks eh, not so great to me even in a desert-y place. Idk, just an opinion and a suggestion.
If you remember the gen one anime when ash fought Brock and went through the city there a lot of things where dirt and rock. I think the dirt fits the city, since there's a lot of dirt and rock type animals there. Maybe cobblestone here and there would make it look more rock.