The new series will debut in early 2016. If successful, adaptations of some of the other Brooks novels will follow (although, presumably, not all thirty of them).
The trailer looks promising, more promising than the so-so source material (the Shannara books are strictly entry-grade fantasy, although Elfstones is probably the best of them) may have indicated. The books are fairly straightforward epic fantasy, but Brooks does introduce some distinctly weird moments in them and occasionally brings the setting's post-apocalyptic backdrop into use in unexpected ways. The books do evolve as they go along, however, with airships and the hints of advancing technology along the way. The trailer plays up the post-apocalyptic elements more strongly than may have been expected, whilst the visual effects are extraordinarily good. There's also some nice moments of genre self-referencing, particularly the casting of John-Rhys Davis (best known as Gimli in the Lord of the Rings movies) as the King of the Elves.
As a more family-oriented take on fantasy, this should prove an interesting contrast with Game of Thrones and other upcoming fantasy projects.