Ship interiors are home to some of the best content in other space games, and while the feature poses challenges, I think they're surmountable and it's well worth Frontier doing.
Some thoughts:
- I think each ship interior should programmatically be in a different space than the spaceship flight. The lack of windows in ships helps, and for the cockpit window itself (when out of the seat) it should be possible to draw a viewport onto the "spaceship flight" space from the "spaceship interior" space so you can see what's happening outside.
- Internal to external space mapping doesn't have to be perfect. We can fudge the Sidewinder.
- They probably shouldn't try too hard to make things like inertia during turns or even general zero-g accurate. They already don't!
- You should be allowed to just teleport from pilot seat to exterior, and back, if you want.
- There can be a significant degree of modularity. Each ship interior would be: a) living quarters (may be same/similar between some ships), b) key reserved spaces like the cargo bay door and where a vehicle hangar goes, c) core/optional internal spaces and d) a network of corridors connecting everything. All the cores/optional internals are of course modular between different ships.
- A size X+1 module will likely need to be more than twice the size of a size X, to account for awkward ship size scaling. An Imperial Cutter isn't really that much bigger than an Eagle but it's roleplaying that it is, and it doesn't hurt to just make the big modules look bigger to fit the vibe.
- Telepresence could allow you to holographically 'return' to the cockpit instantly if you suddenly need to fly the ship.
- Customisation options for real money. There's a lot of room for revenue generation here for Frontier.
Then... gameplay! Awkwardly this is an RPG that uniquely has many fans who frame progression mechanics as power creep, when they're just core to the RPG experience. It's awkward because we can't introduce gameplay inside our ships without giving us something worth doing, and that means progression / power creep. My idea is module tuning, a skill-based manual activity that has a secondary effect of increasing module integrity (not a repair, but an overshield effect), but a main effect that's more interesting and specific to the module type.
The ideal balance would see most tuning not improve the core properly of the module, like an FSD's range, power plant's power generation or weapon's damage. Ideally it's genuinely worth tuning
some modules depending on what you're doing, but not worth bothering with all unless you enjoy it. e.g. tuning an FSD might reduce cooldown times and heat generation, which would save explorers time for long trips (esp. if they're skilled and can do it fast) but non-explorers might not bother. Getting out in an EVA suit and tuning your weapons might just save on heat generation and not matter for some builds.
Other than tuning, ship boarding is a huge area of gameplay. It'd interact amazingly with existing hostage rescue missions and it'd be able to use a lot of Odyssey content. It should offer another way to do piracy, as well as a way to outright steal ships, and we could get experiences like salvage operations boarding derelict ships – classic sci-fi stuff.