^But that's just it -- after a while, once the show has established its own identity and direction, it wouldn't be trying to follow the same storyline as the novels anymore. It would be constructing its own version of the universe that might draw on elements from the novels but would put them together in its own distinctive way. It's just natural that over time, the two versions of the work would diverge more and more as the differences increased.
To offer sort of an inverted example, consider The Hitchhiker's Guide to the Galaxy. This started out as a radio serial and then a couple of record albums before it became a series of books. The first book was pretty much a straight adaptation of the first few episodes of the radio series, albeit with an altered ending so that a cliffhanger moment in the radio show had a more conclusive resolution in the book. That meant the second book had to shuffle things around, still incorporating a lot from the radio series but putting it together differently, leaving out some bits, and adding other bits. It ended in much the same place that the first "season" of the radio series ended, though. But then the third book ended up going in a whole different direction from the radio series, with only a few points of commonality (in fact, I think it was largely based on an unused Doctor Who pitch), and later books just diverged more and more radically, so that most of the material in the second "season" of the radio series never got adapted into prose (or indeed any other format as far as I can recall).
I understand - its just hard to discuss since you have not read/seen it. I would be very interested in having the discussion once you have. It just wouldn't work with this series. Now what would work - is a tv show based on the world with an all new plot and characters. But if you were going to change the overall plotline, you would have had to change the beginning as well. There is stuff happening in the prologue that sets up events in book 5 and so on. What the show is excellent at doing is adding in new scenes with various characters, showing their POV that you don't get in the book, fleshing out a lot of details, and definitely changes its fair share of details throughout. I'm just speaking in broad terms of the general direction the show is driving (the overall main plot) - is still staying consistent. How things get there are changing (which upsets some fans, me I don't care) but the destination in the end remains the same.