Audiences and critics agree that Good Omens has proven far superior than American Gods when it comes to bringing the vision of Neil Gaiman to life as a television series. Amazon's highly-anticipated adaptation of the apocalyptic comedy Gaiman co-wrote in 1990 with Terry Pratchett opened to great acclaim, earning a 82% Fresh rating with critics on Rotten Tomatoes and a staggering 93% positive audience score.
This is far better than the most recent season of American Gods, which received only a 58% Rotten rating with critics and a 67% positive rating with fans. Those numbers don't sound so bad until they are compared to the numbers from American Gods season 1, which earned a 92% Fresh rating with critics and a 84% positive score with viewers. The drop in positive reviews coincided with a major drop in the show's ratings, with one-third of the audience vanishing between seasons and one-third of the new audience disappearing after the season 2 premiere.
This begs the question - why has Good Omens soared where American Gods stumbled? One key factor seems to be the limited scope of Good Omens, which was always planned to be a six-episode mini-series. With the entire series released at once on Amazon Prime, audiences never had the chance to grow bored waiting for the next episode, as many did waiting for American Gods' latest weekly release on Starz (following an eighteen-month gap).
The shorter run also benefited Good Omens by forcing every episode to remain tightly focused on the main plot, without a lot of digressions or new material being added. By contrast, many felt that the new material added into American Gods season 2 existed only to pad out the story rather than to expand the plot or develop the characters. For every good aspect like the flashback episode detailing the death of Thor or the life of Mad Sweeney, there were two to three entirely extraneous subplots, such as Mad Sweeney and Laura Moon's journey to New Orleans to seek out the death god Baron Samedi.
It seems likely, however, that the main reason Good Omens has done so well compared to American Gods is that Neil Gaiman wrote all six episodes of the Prime series, acting as the series' showrunner. This personal attention from one of the novels' creators ensured that the series would remain true to the original story and emerge as a single creative vision. Compare that to the fiasco that American Gods became after the original showrunners were fired, several key members of the cast quit and the replacement showrunner was fired before the editing of season 2 was complete, and it is not hard to see why Good Omens would become the better-regarded adaptation.
Sadly, those fans hoping that Neil Gaiman might turn his attention to American Gods now that Good Omens is over are destined for disappointment. Gaiman shot down rumors that he would take over the showrunning duties on American Gods back in January 2018, saying that he would be spending some time with his family before shifting his focus back to novel-writing as soon as production on Good Omens was done. This likely means there's also little chance of Gaiman taking a hands-on approach to overseeing the adaptation of his classic graphic novel series The Sandman.