GL orignally said the Star Wars saga was 9 episodes, with three extra episodes possible that dealt with some of the characters rather than the main plot. he dumped that idea quite quickly, and lost heart in doing a (rather pointless) final three more recently.
It is also clear that George cares very, VERY little for the Expanded Universe. And why should he? If I created a Universe, I might be willing to make money out of it by licensing it out, but there is no way I'd let anyone else make an intellectual contribution.
Any EU plotpoint that made it to the big screen only did so because it was in George Lucas' early notes, scripts or books- Coruscant is such an example.
Be very sure. Lucasfilm and Mr. McCallum have been issuing statements about Boba Fett because they are creating a VERY different background for him. Any other EU plot point in the way will get a similar chop.
GL did try to plan ahead to stop this happening, by creating lots of "Off-limits" zones for the book writers- the CLone Wars are such an example. But either he forgot to put such a ban on Fett, or he didn't originally intend to bring him back.
But EU fans shouldn't be at all worried. Just enjoy what you enjoy- if it isn't relevant to the films, so what? Persoanlly, I dislike much of the EU output, for all sorts of reasons, but it's all just personal. But the fact is that any relevance they have to the main films is very, very circumstantial at best.