I think, and I could be wrong, that this hints at the tone of episode 8.
JJ does weird and awesome very well. But he's not particularly good at Dark.(See Fringe and the Star Treks.)
Meanwhile this new guy did Breaking Bad. That's Dark as ****. So it seems to me we're going to see some Empire Strikes Back story darkening for the middle film. Then we'll get another epic director for episode 9 to wrap it up.
This may reveal more about me than I really want it to, but halfway through the first season of Breaking Bad I told my wife "I can't watch this anymore. This guy is like the Emperor; he's completely evil, and the story isn't really about him but about how that evil twists everyone around him. And I don't think I can watch him do that."
And I was right, and it's some combination of spooky and cool that now the same showrunner gets to play with the actual Dark Side.