Selenas are more or less the equivalent of our Moon, so those patches would be the the equivalents of "Maria
", flattened basins originated by crust activity, which melted the rocky mantel, caused perhaps by major impacts or something similar.
Pretty standard in all selenas.
If those blotches are supposed to be maria, they definitely need to be improved. First of all, maria have well defined edges; these are just sort of subtly there. Second of all, the terrain doesn't change. Like you said, maria are flattened basins, but in SE, they have the exact same terrain as any other part of the selena. The only thing that tells you it's maria is the orange hue. Lastly, is it just me, or is orange not the way to go for maria? In real life, maria is dark, not bright orange. Overall, I feel that they're just repetitive and ugly. (I'm not mad, I'm just a scientist who wants accuracy
"Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space." - Douglas Adams