The problem with AFFC and ADWD is that if feels the story stagnates and it does not move too much forward, mostly because of the way the chapters were divided, not in chronological order, but instead based on geography, until the second half of ADWD. We have been used to a chronological order for the first 3 books, and then in AFFC half of the characters we expected to read more about disappear only to appear in ADWD, but then again, the story starts at the same place it was left in ASOS. So for two books we are left at the same place.
I wouldn't call AFFC or ADWD bad books, I thoroughly enjoyed my time with them, but they don't feel as satisfying as the first three, mainly, of course, because there is never a conclusion to anything.
I do hope there is some sort of conclusion in TWOW, so we are not left with this feeling again. I'm not waiting for one, though.