As someone who's read a good amount of the Star Wars books, this could actually become the best thing that happened to Star Wars in film, because while everyone loves the original trilogy out of nostalgia (and a bit of hipsterism, from the younger people), the fact is that the authors who've added to Star Wars history/lore with books write much better Star Wars than Lucas ever did. Lucas was kind of an idiot and a lot of the original trilogy was written by other people and succeeded in spite of him. Some of the follow-up series and books are outstanding books even without the Star Wars setting and could translate amazingly into a movie trilogy.
But it all depends on what storyline Disney chooses to make. Retelling the story of the Knights Of the Old Republic video game or the Thrawn Trilogy would be amazing. Perhaps the Vuuzhan Vong series as well (though the Vong would probably freak people out because the concept of them is, well, interesting). But as long as they don't choose one of the cornier, kid-oriented Star Wars series, they have a lot of potential.
But even if they're great, people will mostly hate them because "oh my god they're making more star wars nooooooo."