I love seeing the Death Star right at the start! Yes, this is a Rebel story. But it's equally about the 600-pound gorilla of scary weapons. We're going to be fighting (over) the Death Star, so we may as well get its reveal early on. It also helps me care about Jin and the others from the start: we need you to survive to fight this thing later on.
The opposite, delaying Vader's reveal, is also a wonderful improvement. It gives Tarkin and his Death Star more screen time to shine as the biggest baddies, before Vader commands the limelight.
One small transition detail: the establishing shot of the Rebel base, after Vader's bacta tank, feels short. I'm wow-ed by Vader's entrance and while I'm still processing that, this shot comes and goes. Perhaps a few more frames on the exterior of the base (and fewer on the Rebel listening to headphones).