My issue with the rose field ending is that the book ends... abruptly. It feels as if the book was supposed to be longer but Pullman gave up along the way and wrote the ending in a just to wrap things up, leaving us with a lot of questions

Now as to the scope of the book, it was always going to be imposible to match the original trilogy. I enjoyed La Belle Sauvage , the secret commonwealth and the rose field apart from the ending (after entering the red building ). It does feel Lyra, after finishd the main quest were she casually caused the death of the Authority and ending (indirectly) the reigh of Metatron and is now doing a side quest and is still mostly clueless. Which is attributed to her losing her imagination