Arguably, framing Hardin as a "Hero's Journey" is the show taking chances versus the relatively much more dry source material. As Seldon says time and again, psychohistory can only predict the actions of large enough groups of people, it cannot predict the actions of individuals. From that perspective alone, I've found so far I mostly appreciate the twists the show is taking on the source material. Most of them seem to me to be individual actions within the overall predictions of psychohistory (treating the books as one prediction versus reality/timeline and the show as another).

Particularly since one of the two characters on the hero's journey for a majority of fans turned evil in the last two episodes. And that the one who ended up in the seat of power at the end had a different kind of journey.

GoT was also a Hero's Journey story. The difference is that it involved more than one character i.e. the Starks, etc...