HBO Dodged a Bullet By Avoiding Ill-Conceived Aegon's GoT Spinoff
Despite all the fan complaints about its later seasons, and particularly its finale, Game of Thrones was a ratings giant from beginning to end.
Its enormous popularity ensured that the franchise is going to continue – in the form of spin-offs and prequels, if a sequel does not seem to be viable.
And given that George Martin himself seems to be more interested in detailing the past of his world of Westeros, than in advancing the timeline by finishing his main saga, which spawned Game of Thrones and everything else, prequels were a natural choice.
And a correct one, judging by major success of House of the Dragon.
However, before developing any new series, HBO had to make a choice: which period of Westeros' history to use? The Dance of the Dragons, the disastrous Targaryen civil war, was not the only possible choice.
They could have attempted to put Dunk and Egg stories on the screen. Or to set a new series in another period of tumultuous change: the times of Aegon I the Conqueror and his conquest of Westeros.
However, passing that time period in favor of putting the Dance of the Dragons on the screen, was also a correct choice. First, that civil war was undoubtedly the part of the past to which George Martin paid the most attention, and his in-setting Westeros history narrative, the most complete version of which is currently Fire & Blood, was initially focused on the Dance and the events preceding it.
And second, it just makes for a more interesting story. Aegon's conquest was mostly a one-sided stomp in his favor, through superior draconic firepower, and where he did encounter effective resistance (in Dorne) it was not written either convincingly or in a way that enabled interesting plot interactions.
The only major characters of the time were Aegon himself and his sister-wives, with everyone else being hardly more than background.
Meanwhile, whatever you can say about the Dance's participants, both sides were certainly full of memorable personalities, with conflicting goals and ambitions (moreso in the books, House of the Dragon has a tendency of making its characters into victims of circumstances). And the whole plot just begged to be turned into a script. So, choosing House of the Dragon over the times of Aegon the Conqueror certainly wasn't a mistake.