People forget how radically storytelling has changed on TV. There was a time not that long ago when having a series where each episode continued the story directly from the one before was unheard of. The majority if not all of the episodes were bottles or filler. Babylon 5 was radical in its day because writer J. Michael Straczynski knew how he wanted the story to progress over multiple seasons, up to its climax. But the business of producing TV hadn't caught up, so he had to write trap doors into his main characters to explain why they might not be there if contractual business didn't work out. Imagine if David Benioff and D. B. Weiss had to weave opportunities to kill off and replace Tyrion Lannister or Daenerys Targaryen because it couldn't be known if Peter Dinklage or Emelia Clarke would choose to stay on GoT next season.