Game of Thrones worked so well (at least the first 6 seasons) because the writers/directors cared so much about the source material and did their best to make it as faithful as possible.
Oh Netflix is doing it? I'm intrigued.
I haven't read A Song of
Fire and
Ice. I tried to, but I couldn't enjoy it since I already watched the series, or what was released, which at the time was only up to season 7, so i am not 100% sure, but I thought that the writers deviated from the book series around season 4. Season 8 sucked ass, but that is an entirely different story, and not related to the lack of source material at all.
Martin has said that the show is "their baby" referring to the writers of Game of Thrones and the series, "A Song of
Fire and
Ice" is his show.
I agree with the fact that seasons 1-6 were really well, and I even enjoyed 7 immensely, but I don't agree with your reasoning.
I do think that the igniting of someone's spark should be done as a climax to a season or multiseason arc, or it could be done in the first five minutes of the first episode, much like how Thanos died in Endgame because Thor went for the head. Fun fact, the writers said that Thanos let the avengers kill him then, and if anyone cares, I would be happy to explain that point. I can totally see them doing that and then the series is about coping with this new found ability to plansewalk or something.