
Originally Posted by
DigiFluid
Star Wars canon is defined by Lucas Licensing.
Pre-Disney, you are correct, there were several 'tiers' of canon precedence. "G-canon" were the films, which were regarded as indisputably correct, no matter what other sources said. "T-canon" were TV shows, which trumped any 'tier' below, but if they contradicted the movies, it was the movies that were correct. "C-canon" were novels, comics, and video games, which were fine and correct, until and unless they were contradicted by the TV shows or movies, etc. and so on.
Now that Disney is running the franchise, this is no longer the case.
As of April 2014, everything filmed, animated, or published, is part of the official canon (with certain obvious exceptions, like the Lego releases). There's no debate, and personal opinions carry no weight--this is the official policy and practice of Disney, Lucasfilm, and Lucas Licensing, and is meticulously managed by the Lucasfilm Story Group.
Naturally everyone is welcome to read or watch whatever they choose or choose not to, but that doesn't change the official, factual status of the Star Wars universe and its various entries.
In the new Disney/Story Group era, there is no longer any latitude to complain (as an example) that something in Rogue One wasn't explained, when that explanation was in the tie-in/prequel novel Catalyst--both those releases are officially full and equally weighted contributions to the Star Wars canon. Your (the proverbial you, not you in particular) choice not to read the book is not a failure of the filmmakers. In the Story Group era, skipping Catalyst and complaining that Rogue One confuses you would be no different than skipping Empire Strikes Back and then complaining that you're confused by Return of the Jedi.
This is not to say that the filmmakers aren't going to try. Certainly, it's in Disney/Lucasfilm's best financial interest to make sure that the movies are as accessible as possible, since they by far are the moneymakers for the studio. And I think they've done an excellent job so far of making sure that the films stand up without needing to read the tie-in materials. But that material does exist, and its status as part of the canon is not in dispute.