The stakes are not nearly as high as GOT. Also, it's fairly redundant - Everybody wants to be the next king, including a blond Targaryen woman who also happens to ride a dragon. Gee, where have we seen this before? Reminds of all of the hype before the third Star Wars came out - Return of the Jedi. And what was the plot? The rebels again had to blow up a Death Star. One would think after how bad the GOT folks botched the final season that they would have something new to say in HOD.
Yeah, it's really just for fans who want to experience more of that world. There is nobody we want to know more about. So we already know how the important stuff goes. If they would have done Rob's Rebellion we'd have more interest in learning more about those characters we are already familiar with. Then they could have built up intrigue in characters from HOD.
Game of Thrones held my interest largely because of compelling characters. I have only watched three episodes but I have yet to see a Tyrion Lannister, Jon Snow, Arya Stark. Even minor characters like Lady Olenna and the arc of Theon kept me interested. So far no equivalent.
