I like to think of things in different levels. If you adhere to the original movie being it, that really doesn’t fit in with the idea of canon so here is how I look at it.
OT - Platinum Canon
OT & PT - Gold Canon
OT, PT, & ST - Silver CanonThis makes sense in theory but not as much in practice. The PT is well…the PT and the ST isn’t even close to being over. Pretty premature ranking in my opinion.
Well, it basically is a chronology of when they were released. Plus the episodes over the other movies and series (with a Clone Wars character appearing in Rogue One, that sort of places them in the same category in my mind). If the rest of the ST sucks, well, it isn’t as important as what GL did. But so fare I like it better than the old EU.