There are quite a few things they could do to add some life and diversity in our current maps without completely changing the terrain layout or palettes. The problem is they didn't even bother doing this.

Take Coerthas, for example: The raptor areas could be full of grass. The grass is already there, just take the grass object, paste it all over the place in different sizes and angles, and you have a unique grass-field within Coerthas without altering the terrain.

Making a pine forest could be just as easy in the stag areas. It was definitely easier to just paste the generic group of objects all over the place without thought, however.

Personally I don't even care about landmarks unless they actually put some thought into it: Take Coerthas again, for example. There are a lot of structures scattered across the map (mills, buildings). The problem is they feel more random than something that was actually put there on purpose to me. Mobs run into them, and there isn't any sign that anyone either lives there or ever did.

Our current world needs a lot of love, and I'm not only talking about layouts. While the Black Shroud needs the most, it's definitely not the only. I don't know how much of a priority going back to every area and making sure most corners feel "right" should be for the development team at this point, however.