Little Linguist video here, for an example of Ne thinking in an Ne dom.
So, yes, totally extroverted, but also the environment scan induces a lot of inside-the-head thoughts.
In INTPs and INFPs, Ne doesn't work quite that way, working from the environment first. Instead, the INxPs start off with Ji, and then Ne will often jump from there. The process can also be Ne->Ji, but usually it's from inside to outside for the introverts. This can result in creative story telling, as I depicted earlier, or it can just be their attempt to express their thoughts (Fi or Ti), using Ne to figure out the best associations to turn their ideas into words and communicate them (with varying degrees of success).
In other words, Ne is extroverted, but it isn't always the dominant function. Other people use it differently.
I'm fairly sure from his writing that Joss Whedon is an INFJ. I get the feeling that he uses Ni to develop a strong background, and then uses Fe to determine how the story should play out. He's partially using Fe to figure out what would be a dramatic and effective story, as well as for portraying the various characters.