I don’t believe Lucasfilm or Disney should dictate what is or is not canon. I think the fans should decide this. Just because Lucas decided that he wanted to put a young Anakin at the end of ROTJ and have Han shoot first doesn’t mean we have to accept it as canon.

Likewise the prequels should not be considered canon, because they’re bad films and because of the numerous discrepancies between the prequels and the OT. Basically, we shouldn’t recognize anything prior to ANH, and that includes the Clone Wars cartoon.

The prequels will only get worse with age, and I strongly feel that maybe in ten years, Disney will succumb to pressure from the fans and retcon them.

I think the same will eventually happen with TFA, and Disney will realize they should have brought the Zahn trilogy to the big screen instead of Jar Jar Abram’s boondoggle.