I think the marketing for RO has been spot on. They've established the main characters , the places , and the links to the SW universe very well, but with minimal information as to how the script manages to pull it all together ,so the overall mystery about the story is preserved but enough of the groundwork has been done to keep people very interested.
And perhaps even more so than TFA, RO really does promise that journey back to galaxy a longtime ago so far,far away (nearly forty years for a few of us!!!) whilst cleverly making it more relevant to the more recent canon, such as the prequels and TV series.
That kind of generational bridging is almost unheard of ,but it means there is a massive range of ages across whole families that are likely interested in going to see this. And lets face it who does not want to see Vader REALLY going at it in full sith combat mode (I hope).