The devil is in the details.. In any environment to make it believable and immersive, its the details that have to done right. From plants or insects or weather and day night cycle, it looks like wild star is on the right path.
I have to say this, being inmersed in a game is the most important thing that you have to make sure to pull out properly, it doesn't mather if it is metro last light or minecraft, you have to get inmersed in a game to enjoy it, even a fantasy MMO.
Inmersion and realism are totally diferent concepts, you can feel inmersed in a dark dungeon from dark souls, while you are fighting demons and alike, or feel the darkness of the ambient while playing any batman game (at least the last ones, which are holly-<REDACTED> levels of good), or feel like a general in total war Shogun.