What comes after "The Return of the Jedi" is rubbish in MY OPINION
George Lucas and LucasArts came up with an amazing storyline after RtJ. Thrawn, Zahn Consortium, Ysanne Isgard, the Yuuzhan Vong, The New Republic, Thousands of comics, hundreds of books...
Gone... just like that...
What I heard, I dont know if its true, but when Lucas was selling the rights of Star Wars, he had a large binder with an outline of what happens after the Return of the Jedi and the Disney rep literally threw the binder in the trash in front of him. That is what I heard...
Thrawn is in the current canon..and is just as awesome as he has always been. But no, Lucas brought his ideas for a new trilogy to Lucasfilm way after the deal was done and they decided to not use it. No overly dramatic chucking in the trash. People have to remember though, the person in Charge of Lucasfilm..Kathleen Kennedy...worked for Lucasfilm directly under Lucas for the last few Decades...she had his endorsement to be in charge of Lucasfilm. Lucas Jar Jar Binked us.