Anyone else remember that the first Harry Potter movie was heavily criticized because it was too faithful to the book?
It was compared to the Lord of the Rings which was released the same year, and which became the good standard for adapting fantasy novels to the screen.
I think the main problem the TV show will face is that throughout the series, the novels evolve wildly in tone and sophistication. The early novels are cartoonish. The Dursleys are clownishly villainous, dead people can be ghosts, Dobby ... exists, Voldemort is a toothless joke that can can be defeated just by being touched by Harry Potter.
The later novels abandon the abject child abuse of the Dursleys, they show that Voldemort's villainy is the serious dystopian threat of fascism, and we just sort of put aside that ghosts and portraits of dead people are a thing if it's any dead character we care about.
This story's evolution in sophistication worked well for books because the readers literally grew up alongside the novels.
Maybe it will work for the TV series as well.