Watched a few episodes with my spouse. So far: It looks great, the acting is good, I have no strong opinion on the directing, the writing is definitely worse than the original.
I saw the first episode twice now so far. Non spoiler summery...
Visually STUNNING. I love love love how almost everything looks (Appa being the giant flying bison sized exception)
Emotionally it feels... stunted. It feels more like the characters as adults telling idealized versions of their memories as stories. Most of the humor is just... gone.
If they were trying to look at a scale from dead to cartoon in therms of over emoting and goofiness and the original was comfortably at 10 - cartoon, and reality is around a 7.... this is a 4
Characters known for emotional decisions and reactions are being calm and thinking things through and respecting other people in ways they do not until after a whole lot of character growth later in the series.