Guess who’s back!
Since they’re apparently going to visit the wreck of the DS2, I’m guessing Palpatine might appear as either a Force Ghost, or more likely, as some kind of Force Vision. Might be similar to the Thrawn trilogy where the death of the Emperor left behind an imprint in the Force.
Or Lucasfilm could just be messing with us in the trailer. Wouldn’t technically be the first time.
Both Death Stars blew up. There was concept art for The Force Awakens of the second Death Star underwater, but they scrapped it. It seems like they could potentially be returning to those ideas, but it also seems a bit odd because the Death Star blew up in space.