I definitely see them going as dark as any point in any Star Wars film has yet, even as far as the younglings are concerned, if the story required. I doubt they'd have to do that, as that was a really extreme point for Anakin, so I don't see a need to hit that point again; but in terms of story and all, there are PLENTY of dark scenes/moments in Disney movies, so I don't see them holding back for the sake of children or anything.
ANH was also the introduction chapter, while ESB was the chapter where everything that could go wrong, did go wrong, and it left the heroes in peril. Then come chapter three, rights are wronged and happiness is restored on some level. That's likely the path these will follow, so expect Episode VIII to be the darker one of the three!
He's had it for awhile.
