Every Star Wars rumor results in people saying please be Thrawn or have a Thrawn Trilogy or something along those lines. There are a few reasons why it is a bad idea and why it won't happen.

The original setting was 5 years after Return of the Jedi. Our primary heroes look a bit more than 5 years older at this point. Since it has basically been confirmed that they will be part of the new series of films on some level it does not make sense to set the films 5 years after RTOJ.

But what if the films are set in a time period more appropriate for our primary heroes? Pretend the books didn't really happen and that Thrawn attacked 20 years after RTOJ. Well that's fine, but one of the most critical plot lines in the story is Luke and Mara Jade. Introducing Luke to Mara 20 years after RTOJ doesn't exactly seem like a good idea.

Also it is the only book that really talks about an Emperor clone. Please for the love of George Lucas please let him be dead. Just like Obi-Wan needs to be dead. The problem someone pointed out with the Pre-quals was just how small this very large universe seems to be. Anakin built C-3Po and all the other crap that went on in the pre-quals. This is a veyr large universe. You don't have to relate all of your new characters to Count Dooku or General Grevious or by bringing back the old emperor.