This has been my thinking in general, in that it looks amazing and fun to design and "live in" a custom spaceship, but if that spaceship just sits on the ground all the time, then I fail to see the point. Sure, you fly your spaceship in space, but is there any other gameplay in space tied to your ship's design and interiors?
Yes.
Is there a damage model and associated gameplay, for example?
It's possible to target individual modules in combat, and thus there's some advantage of burying critical systems like the reactor behind other, less critical modules.
Is there a "repel borders" scenario where your ship is boarded and you a gunfight in your custom-crafted rooms and hallways?
Never had that happen to me, but I'm not very far into the game.
How does ship design affect the flight model?
Sadly, this game doesn't go into the amount of detail that Empyion Galactic Survival does when it comes to the flight model. That game remains near the top, right behind Kerbal Space Program in this department.
Coming from Space Engineers, I have high expectations for the gameplay that involves my spaceship, where every design choice matters,
Nor does it go into the more limited thruster detail of Space Engineers. This game more reminds me of a 3D version of FTL when it comes to ship combat, especially power management. Which is a good thing in my book. It's just not necessary to set up my HOTAS to play this game. At least not yet...
and where I can set my ship on autopilot while it flies a few thousand feet above a planet's surface and walk around and enjoy the views from various windows and portholes, etc. Not that designing and walking around a ship in Starfield wouldn't be fun for me, but I want it to be more than just a mobile base. Maybe it is, and I'm missing something.
There's quite a bit to encounter in space, but much of it revolves around ship-to-ship combat... and naturally you can skip the whole thing via fast travel if you're not interested in that kind of thing. And as you know, there's no surface flight available.
Sadly, there's still no "ideal" space game out there. Elite: Dangerous comes closest IMO, but unless Frontier builds upon the on-foot portions of the game, especially when it comes to exploration, what game you play is going to depend upon what aspects of a game you willing to compromise on, and which you aren't. Starfield has a great planetary exploration loop going for it, but without a procedurally generated galaxy to explore, there's a limited number of planets explore. It also has the best scripted missions, but again those are limited.
ED has by
far the best flight model; an entire procedurally generated galaxy to explore; a decent political simulator; the best economic sim outside of X4 and EVE online (even if it
used to be much better); vies with Space Engineers when it comes to the planetary vehicle physics; and ED would be at the top of my list when it comes to stealth gameplay if it wasn't for the fact that I have to play in
real time.
It's that last factor that causes Starfield to currently scratch my on-foot itch when it comes to space games. But I suspect that it'll be like Fallout 4 in the end: I'll play it for a while, reach a point in the game where it feels just too much like a grind to continue further, and then go do something else until that itch becomes unbearable again.