Just as a translator must depart from the literal words to better convey true meaning, a good adaptation will need to make changes to its source material to do it justice, and to be a successful work of art in its own right.
Altering the plot and even the sequencing are perhaps understandable (even if many of the major twists of the and surprises of the whole series have been revealed by episode 3), but the real disappointment of this adaption is the failure to capture the spirit of the source material, ultimately leaving us with a tepid, generic boxset.
Lyra of the books was so likeable for her pragmatism, vivaciousness and audacity, but the script writers have turned her into the opposite; permanently frowning, angsty teenager. Scenes are either grave and sombre or tense and perilous with no counter-balancing excitement, humour or wonder.
A high production budget alone doesn't create an enchanting world, and the differences between Lyra's world and our own are used as a pretty backdrop but not explored in any meaningful way. Self-conciously modern, close-up shaky cinematography and an often intrusive score do more to take us out of the world than draw us in. In lieu of actual character development there are far too many hammed up, drawn out 'emotional' scenes that seem to be intended to add psychological depth and seriousness but just get in the way of the storytelling.
Worst of all, despite all of that CGI, most of the the daemons seem to be absent or an afterthought. They seem to belong only to a few major characters, conveniently out of shot or out of sight for most other characters, and even Pantalaimon seems to only pop in for scenes when it's absolutely essential. The daemons were Pullman's genius innovation and the novels' storytelling and imaginative centrepiece. Yet, so ripe for realisation through modern CGI, they seem to have been sidelined to make room for the producers' own additions.
Just as The Hobbit was transformed from a unique and magical children's story to a generic Hollywood action film, His Dark Materials appears to have been forced through the mould of a generic high budget TV series, most of what made Pullman's books so special left behind.