30 years into the future mostly means that Luke has already sought out new Jedi. Which makes throwing out the post ROTJ EU an odd choice. They are just going to have to go back and fill in the blanks which were previously filled in, which they will. I understand the freedom and the clean slate needed for new movies, but honestly, what restrictions would they have had? Number of children and names of characters? Is it really that hard to incorporate to? I can see throwing out the entire Vong saga to bring back Chewie, and some of the bad novels, but for the most part it seems like a marketing ploy.
Off topic but I wonder where this EU/Clean Slate leaves stories like Shadows of the Empire?
It's unlikely they do anything in the half of year between ESB and ROTJ. Unless they do, it doesn't make sense to junk it.