As a fan of book series (written by Bernard Cornwell whom also did the Saxon Stories that 'The Last Kingdom' is based on) I have been following the news and was eager to watch this show. To me, the trailer did not look promising given the lack of time provided to the book's central character - Derfel.
While it is obvious that this show would not be a faithful adaptation, cinema often isn't so I went in with an open mind.
The actors do a well enough job with what they are given, but it is obvious that the characters will not be the same as the book series (i.e. Merlin is meant to be senile and old, Morgan is not at all the same). Clearly this happens often as interpretations differ, but Winter King's interpretations are completely opposite to key characteristics for main characters.
While trying to view this property as a stand alone or outsider unaware of the original story, it is certainly better (maybe a 6.5/10 acknowledging my bias), though it provides nothing new or groundbreaking.
To most the show would be used to passably kill time. Entertaining enough I suppose. Time will tell where this show goes, does it get better with time or does it become The Witcher.