This is great news! I realized in the mid '90s that The Star Wars expanded universe had started to get out of hand. I stopped reading the books at that point. 15 years later, it must be completely out of control and exponentially ridiculous. This article on ars technica basically sums up how I feel about the giant dumpster that is the expanded universe.
Now, as a cynic, I won't get my hopes up. This is Disney, after all. They want to make as much money off Star Wars as possible. However, there are going to be people not named George Lucas making decisions about story lines, characters, and other stuff not in the original movies. Worst case scenario, the canon is streamlined and limited to the films and a few books and games from the expanded universe. Keeping things simple, Disney would make some room to write and create after Return of the Jedi, without being held up by an already haphazardly established canon.
However, best case scenario, they scrap everything before and after the first three original movies (episodes IV, V, VI) and throw out everything else to start completely from scratch! I wrote a post all about how to remake the prequels, relying heavily on Mr. Plinket's reviews from Red Letter Media to make my case. This is the chance!
Disney could throw out the notion of midichlorians. They could rewrite the rise and fall of Anakin Skywalker, tossing out the "slave boy rescued from Tatooine" nonsense. They could create a better, more plausible conflict that would be known as the Clone Wars. Finally, Jar Jar Binks could be just a memory of a bad concept that fans rejected, instead of a recurring character that fans have to vehemently loathe.
io9 published a story the other day about this, as an open forum for fans to put in their two cents regarding what Disney ought to keep, and what they should toss out. The link is below. The comments are mostly worth reading.