It's remarkable how American Dad manages to break out of its confines once or twice every season. This episode is one such occasion and it over-delivered if you have a sense for fiction that is more than just the silly 2-dimensional laugh track wrapped into a 20 minute cartoon.
The episode is a deep dive into Roger's origins on earth. It blanks out the Smiths and every rule established about the universe of the show. The humor is there and keeps dripping throughout the episode, but it is dialed down and remains behind the plot only supporting it when needed.
I love these expansions, which are the only way of keeping a fictional series of this kind alive. It has to break with its own conventions at one point. Otherwise it falls into a feedback loop of vapid repetition. Few others manage a similar turn and renewal, Archer would be one such current example, South Park as its own category another.
Others though, from The Simpsons, to Family Guy and increasingly even Rick and Morty fail in this evolution. The audience of American Dad may be smaller than theirs, but those who understand and appreciate the creativity behind the show's takes and perspectives will certainly stay and applaud.