I agree with those guys, i found the map design solid overall, the mapping itself was solid as well. But like said already, the theme just doesnt carry, i say nix the planet in the sky, as people will just wonder wtf is going on, it really doesnt add anything, or you could just change the map name to Cp_2Earths.
As a tf2 env artist, id also have to comment on your custom props, the texturing is barely passable for tf2 styling(to much noise, not enough abstract), and the normal mapped rocket engine looks out of place, would have looked better with just a diffuse and spec/phong. Your colors are way oversaturated as well for the red and blu.
I think a tf2 space base theme could have been really really nice, i would have liked to have seen you go more in that direction considering you had the resources to do so, as it stands, it looks a bit to much like your average tf2map, in terms of styles, architecture, textures, ect to really distinguish itself from the crowd.
Still one of the better custom maps out though!
-Buddikaman-