The writing/dialogue is laughably bad. Like legitimately one of the worst scripts I've ever seen.
It is humorless. The original run was unique because of the dark sense of humor interjected throughout the voiceover and in the dialogue by the lovable side characters. There was so much that could have been done to punch up this script in that same vein--some tongue-in-cheek acknowledgement about how ridiculous this scenario is or how badly the previous series, etc.--but instead they seemed to opt for extraordinarily lame, by-the-numbers Lifetime movie writing.
It is drama-less. We haven't seen Dexter in a decade and the opening shot is just him running through the woods in overalls... No build up, no reveal, nothing. Just boring, lazy trash.
The acting is over the top and pathetic. MCH clearly doesn't care and is just doing this for a paycheck.
They went the Suicide Squad route and tried to cover up for a lack of quality by shoving in pop songs into every single scene, even if they don't fit, hoping slack-jawed idiots will confuse a good song for a good show. And it looks like it's working on some of you.
It just looks terrible. Remember how the contrast of the vividness and beauty of Miami with the grim subject matter made the original Dexter so novel? Well, remove all of the color and change the palette to muted orange and shades of gray and here is New Blood. And the CGI deer is the worst thing I've ever seen.