To those riled by it not keeping "true" to the book, surely that makes it less predictable and therefore a little more entertaining. Surely the point is to keep to the spirit and arc of the book, and not the precise plot-points?
By making it a series, they are obviously only going to use the premise and a rough character outline, so it makes sense that it's not going to follow the book which had a definite start, middle and end. For me the storyline was always a bit suss anyway, and the ending was a bit.....well, odd. What made the book brilliant was the characters and how their personalities and true characters came out in adversity, but they are never going to recreate SKs portrayals on the screen so yeah, I can't imagine it remaining true to the book for long.