The Graphic Novels and Concept Artbook
I'd say that the Journey to One had a lot going for it, but didn't get to show everything it could do for the theme due to it being produced with the cancellation in mind. Perhaps if it were an actual episodic series, with at the very least fifteen 20 minute episodes for winter wave, and ten-fifteen 20 minute episodes for the summer wave, we could get a better idea for what would've been. It really didn't meet its full potential.
The thing is, we live in a world where it didn't meet its full potential. We got what we got, and what we got really didn't have any more depth than the animations did. In fact, the animations did more with less run time and only one voice actor. My vote definitely goes for the 2015 animations.