With GRRM, I agree with a_d_medievalist that somewhere in book 3 we suspected that he'd gone off the rails. Or perhaps it was when he didn't wrap up the series with that book as he had originally intended to and then took however long it was to bring out the next one...
One thing I admire about J K Rowling is that she had the seven book sequence apparently prepared right from the word go and knew exactly where she was going, and to some extent it shows. On the other hand, I got the feeling that book 5 was a certain amount of wheel spinning; she didn't really need it to advance the plot arc(s) and that is why it's the weakest in the sequence imho.
One thing I admire about J K Rowling is that she had the seven book sequence apparently prepared right from the word go and knew exactly where she was going, and to some extent it shows. On the other hand, I got the feeling that book 5 was a certain amount of wheel spinning; she didn't really need it to advance the plot arc(s) and that is why it's the weakest in the sequence imho.