That Witcher 3 version existed only in some short videos and sequences, and in edited photos. Developers never confirmed final game will look like that.
With Metro Exodus is different story because devs confirmed that this is in-game footage. They also said that this is ending of one level where you must escape with train, so that's why it's feels scripted.
There is still one year before release, so things can change in terms of graphics. But to me graphics is not important here. It can look like LL if you ask me.