The EU's being rewritten and reset as we speak with the new Dark Horse graphic novels set after A New Hope
. By the time cameras roll on principal photography for Episode VII enough of it will have been changed by book and comic authors that any hopes of seeing a Clone Emperor or the Yuuzhan Vong will be extinguished unless they're used as script elements independent of their original stories from the last twenty years.
The EU is hit or miss in many respects, vacillating between gold medal excellence and being boring and awful. The new Trilogy should strike as independent a storytelling course as possible. Use elements from post-Jedi
stories if you like....done right it could be very engaging for the audience (I for one wouldn't mind seeing Thrawn or Mara Jade). But don't tie down three mega-budget motion pictures that fans have waited decades for to books that a helluva lot of the public have never read.