I'm pretty sure Yoda explicitly told Luke to pass on what he had learned. In the movie. So, it's not like the whole thing is noncanon or something.Hero in a half shell said:I don't really care about him, or the expanded universe. The way I see it all force users ended with Luke Skywalker, thus bringing balance to the Force, so the canon stops there. the Prequels, meh, they'll do, but the real awesomeness was from KOTOR. Because Revan is awesome.
As bad as the majority of the EU is, it's still not as bad as the prequels. I'd declare them noncanon before the EU.