David Benioff and D.B. Weiss have proven themselves to be not only incompetent writers when they lack source material, but also eager to leave projects half-finished when they have other projects on the horizon.  Their respect of lore alone does not make them fit for this project. 

There are plenty of talented writers and producers loyal to the franchise that would make much better work in the Star Wars Universe. 

Subvert our expectations, Disney!