I though they did a good job with the season. They kept to the main elements of the books with adding a few little surprises.
I'm fine with the ending. The writers have always said a season may not be an exact book. Basically, they left off the last chapter. I'm not going to spoil it for non-book readers. Before the season started, I was thinking of how I'd "break" the book if I were a writer. Since the next book begins 1 day after the ending of this book, I didn't think they would end in the book location. I though they'd wait until the next book they include everything from this location. (I hope I'm not confusing everyone.) There's probably a good 9 months in between season filming. That's a long time to keep the set, hope you can get the same actors to return, etc.
I like the TV Bree and Roger better than the book versions. I found the book Bree rather "whinny". In the books, Diana included some of Bree's Engineering degree "inventions". It would be cool if the writers could also use her degree to make some cool stuff. It wouldn't affect the plot, but would be fun to watch.
I so liked the way the Native American's were handled. Terry did such a beautiful job on the costumes. (On twitter, she's spend hours explaining the design/research process. Very interesting.) I'm sorry this was her last season. But totally understand how she needs to be home for her kids.
Season 5 & 6 will be 12 episodes each.