This one is slightly harder to explain. It involves a number of those things already mentioned - the original cast, Kasdan, the incredible cinematography, practical effects and so on - but it's all those things combined and then so much more. Just watching the trailers, or reading about the film, hearing the actors talk about it - basically anything and everything related to The Force Awakens from the past year - gives off the impression that Disney and Lucasfilm really know what they're doing, that they're treating this property with the respect it deserves, and crucially that it really does feel like Star Wars. It's not just some money-making movie franchise. It is that, obviously, but it's so much more. It's magical in a way that transcends cinema and becomes way more personal, and as pretentious as that sounds it's true (all of it). And, based on all of the stuff mentioned before, J.J. Abrams, Kathleen Kennedy, and everyone else involved really do get that. And that's half the battle won right there.