I've been thinking more about the Deltarune Summer Newsletter (2026) that released yesterday, and I think I might know what Toby is talking about? Maybe, maybe not, but I have thoughts I'd like to share.
I've seen some people bring up the line about the chapter being shorter and equate it to Mother 3's Chapter 6 which, if you didn't know, is only like 6 or so minutes. Literally, no exaggeration.
I really don't think that's happening though, but because lots of people online only view the world in binaries and extremes, that's where their minds went when they saw 6 described as shorter (sorry if that sounded mean).
Instead, I think it means a lot of the "Chapter Traditions" we've seen up until now aren't going to be present in 6.
In fact, we already know this to an extent: Chapter 5 had the final Shadow Crystal and Forgotten Man appearance, meaning there likely won't be any time at all devoted to Secret Bosses and Egg Rooms in 6. We even got a "Final Starwalker" bit near the end of Flower Castle.
Additionally, I don't think there's going to be an extensive Light World segment this time around.
Chapter 4 had both the Church scene and the Holiday Manor scene with all the Hometown exploration in between and Chapter 5 had the Festival. Those events added more time to their respective chapters and are part of the reason they're on the longer side. I checked, and several streams of the game I watched began the Dark Sanctuary Dark World roughly 3 to 4 hours into Chapter 4! If Chapter 6 doesn't have anything like that, it would make sense it would be on the shorter side.
I think we will get a brief Castle Town sequence to give the player a chance to restock on items, talk to the new Chapter 5 recruits, and give Seam the final Shadow Crystal, but I don't imagine much more beyond that.
In short, I personally think Chapter 6 is going for more of a medium length compared to 4 and 5. I think Chapter 3 might be comparable, but with the gameshow segments replaced with dungeons. How many hours it will be is anyone's guess of course.
Also, I have an idea for what "focuses on one aspect of the story" could entail. With all the setup, 6 is definitely shaping up to have a massive reveal. And while this reveal won't cover every single mystery in the game like Gaster or the Forgotten Man, I do think this reveal has the potential to answer multiple questions at once.
What happened "That Day"?
Who is the Knight and Why?
Again, I don't think all of these mysteries are going to be solved at once, but it's possible the new information revealed in 6 will recontextualize a lot of the details we've known for years.