A massive positive is that the House of the Dragon screenwriters is dealing with a finished text. Martin completed this history up to the point. Furthermore, the historical nature of Fire and Bloods means that there is more flexibility when it comes to ending it.
They have a barebones outline and can fill in the blanks themselves. It’s fascinating that the new Lord of the Rings series will also use a similar model. The danger is that the writers move away from the heart of Westeros and leave the fans feeling out of place (via Esquire).