There are three things keeping this show from being great.
First is that story only revolves around and jumps back and forth between two characters, second is that the two main characters and pretty much everyone else, besides Otto, is either bland or not given enough time to get fleshed out and third is that they are unnecessarily fast forwarding through the story.
We're still early on in the show but
@dora_da_destroyer and others already touched up on there not being any real evil characters in the show, which is not a problem, problem is that there aren't many characters in the gray area either. Otto was the only one that fit the bill and actually got airtime.
Corlys and his wife have inexplicably been removed from the storyline when they should be playing a big part.
I don't even know the names of other King's council members, there's that one fella that pops up from time to time to give great advice that's always discarded. And the rest of the 'families' are just fodder for Rhea.
Viserys is one dimensional, a good guy but incompetent, while Rhea was not given any character development at all. I thought Rhea's conversation with Rhaenys about the role of a woman/princess would be the turning point for her but then she goes on to have the same conversation with multiple people while not having any growth at all.
First Rhaenys tells her, then Luke Wilson tells her she's lucky to be in her position, then her uncle tells her the same thing and then in the end Alicent tells her the same thing and Rhae seemingly ends up converting Alicent to her side