Don't stop there at Death Star Hallways...
Echo Base
Mos Eisley Cantina
Cloud City
Or forget modularity and do more like Jabba's Palace...
Lars Homestead
Sandcrawler Interior
Millennium Falcon Interior
Star Destroyer Bridge
Yoda's Hut
Ewok Village
Wampa Cave
Home One Briefing Room
Those are definitely some nice ideas. I think what's great about the Tantive IV hallway is the way you can build on it and put multiple sets together. It's definitely got me thinking about some specific locations and how Hasbro could present them in such a way that one set would look great, but combine them and you could make something bigger and cool.
But I don't think the concept would lend itself to every kind of environment. The Jabba's Palace Adventure set is a perfect example. That alcove is unique to one section of the audience chamber. An add-on section with the archway where Jabba's dais is located seems like it would be a good companion piece to the original set.
With Death Star hallways there has been a lot done with third party makers. But how do you present it in a mass scale? I think a format similar to what we got in the Tantive IV hallway would work well. What seems to be specific to the Death Star in Imperial architecture is that the walls are pretty much vertical. The way I think it could work?
-2 x interchangeable wall segments
-Opening/closing blast door
-Turbolift door / chamber or the semi-circular pillars
-2 x floor sections
-Imperial Navy Trooper pack-in (possibly in Kenner style deco)
I think a similar presentation would be great to do with the Imperial cruiser and base corridors. But those corridors tend to be angled and have the braces that are spaced at a regular interval. And what's great with these is that they tie in well with The Mandalorian. And definitely include a pack-in figure that would be specific to The Mandalorian!
-Blast doors
-4 x braces
-4 x wall segments
-Floor segments
-Dark Trooper pack-in figure
You could almost certainly make a First Order set with a similar concept to the Imperial sets. The main difference seems to be that the angles of the walls are significantly different - Imperial walls angle inward, and in a First Order corridor it's narrow at the floor and widens out at the ceiling.
With the Cantina it seems like things might be a bit more open ended. In this case I think that Hasbro could make a couple of different sets to depict different parts of the Cantina.
ALCOVES - These would be the booth sections of the cantina. Closed in and with seats and a table for each alcove. Do you keep it to one alcove per set or maybe two? That would be a point of discussion. For a pack-in? A TVC Cantina band member with all of the instruments. But I would also be certain that the Cantina band members would also be offered as a mainline figure so that you wouldn't have to buy 6 playsets in order to get all 6 band members.
THE BAR - I think this should get done in a similar way to the OTC cantina segments. And in this case maybe split it into two sets. Each set could present half of the U shape of the bar and half of the distillery segment in the center. In the first set pack-in a TVC Wuher. I'm not sure about a pack-in for the other set, but someone specific to the Cantina that's worthy of a TVC release.