I love it! You really captured the lighting very nicely in this, and also the plants come out very well. Too bad for the one exploded dude on the near left. I would simply copy brush it away in post. In case you are planning to do a second iteration, I would reduce the reflectivity a bit, also reduce the density of the bigger stones (but that's just me).
Why wouldn't the terrain take populations? The only thing where that occurs and, I discovered lately, is that when your procedural terrain fades out through a blended distance shader, the population won't sit on the terrain. Is that what you do in your image? Otherwise, it should work.
Anyway, this image is beautiful, thanks for showing it!
Cheers,
Frank