I don’t know about Barrett being just an ordinary person. Whoever he is, I don’t think we’ll be finding out until next season. I’m leaning towards Peter Pan (although I’ve said a million times that I’m still hoping Nealfire turns out to be Peter).
Being from our world doesn’t have to mean, that he is ordinary, or ordinary only in the sense, that he has no colorful magical realms past. The more I think of it, the more I like the idea to bring someone from our world into the mix. Access to magic, dark magic, means to power – that can be tempting. Not sure if this Barrett is it, it might be too early to bring up such a story arc, but think it would be interesting to explore it.