Multiplayer is a key concept for ship interiors, and my guess is... also the biggest problem. I'd say ship interiors are more strongly oriented to multiplayer than any other interior space in Odyssey. Players get together and go on missions... inside their ships. No matter where each player joined the mission team from (surface, station, another ship, etc.) all are inside the ship together before, during and after a mission.
So big problem I have always imagined with Elite ship interiors... What happens when a pilot pushes the FSD button, the boost button, or even just does a barrel roll when any or all players inside their ship are not in their Remlock seats?
Do they splat against the walls and die? Or fly around the cockpit like rag dolls? Sure there are mag-boots, but just how strong are players ankles to support their bodies during say, combat maneuvers, when a crew player wants to head back to jump in a SLF?
What about a CMDR who needs to jump out NOW to save the hull from destruction, but some player is out of their seat, or even wounded and incapable of returning to their seat?
I'll presume that the entire idea of hull breaches, interior combat, and then stealing another CMDRs ship would be impossible. Otherwise, we'd have ship gifting/trading become a thing, and much more.
I'm not saying these issues couldn't be resolved and still have a coherent Elite lore and whatnot. Just that it might be a massive undertaking just to figure out how all of these (and probably many more) issues must be resolved.