There are some really great kids books I’ve read to my daughter that I think would work well in a visual medium.
In particular the work of Alastair Chisholm (Orion Lost, The Consequence Girl and Adam 2) would work well I think.
Also Jamie Littler’s Frostheart series would be great.
I’d also like to see an adaptation of How To Train Your Dragon that’s much closer to the books than the movie series of the same name. The books are so good but so different from those films, and their story and characters would make a great TV show IMO.