FDev could definitely organize a "crowdfunding" campaign in their ARX shop to check if the demand for ship interiors could cover the price of development. Worst case they would just refund it saying that not enough people bought the perk.
In terms of implementation (not saying for all players) I think it would be sufficient just to:
- Allow to stand and walk in the cockpit (maybe redesigning pilot seat so that it can rotate 180 degrees if cockpit is too narrow to walk) and the door leading to elevator-like room.
- Allow to use SRV bay as an entrance/exit, which would do nearly the same as it does for SRV, but for the pilot body. When you stand in highlighted area underneath and then use embark menu, which starts short animation of pulling you in. Exiting the ship would work similarly to dropships, but while ship is standing on the ground. So minimal changes to current blue circle implementation, but imo more immersive.
- Rework ship entrances and put some sort of air-lock room (with access to ship storage) with automatic door and if needed a ladder extending together with the landing gear (for ships having entrance too high, like FDL).
I also like the idea of having some elements of base building in the game. Just allowing to buy and deploy a settlement of chosen type (e.g. on a planet which has no other settlements) and generate small subset of missions to allow changing its status and eventually upgrade it (to add more barracks, landing pads etc).
I would also like to be able to find an asteroid large enough (similarly to finding hotspots) in the ring (or asteroid cluster) to create asteroid mining base. Maybe allowing to define the rules - like arms-free zone as all current spaceports and FCs concourses or pirate base without such a rule (so that you can visit it on your risk, but potentially find there stolen goods with cheap price, or pre-upgraded ship modules in a way similar to pre-upgraded handheld weapons on stations).