Been thinking about this mission thing, how does this sound for a system open ended and free but allowing people to chase immersive content?
Ive split this into two sections one ground side and one space side but its all much the same system.
For example ground side (fairly certain theres a ground components this time round), the player would see this :- you have an aggressive narcotic addict npc with a need to make cash by stealing stuff ground side, he kills another npc and robs him, whilst in the process a police npc comes into sight, the aggressive npc may then flee. therefore the police ai in response place a fugitive tag on that npc, the npc members family of the deceased may place a contract on the aggressive npc, etc etc.
By giving npcs goals and actions and letting them sort themselves out, the npc interactions could give rise to missions you can take. (I would assume that not all cargo missions come from the coriolis station) Its all stuff that can be written into code fairly easily as far as I can see, the setting of values and needs isnt too much of a problem, all you need is scripts to support the actions needed to satisfy those needs, then let the needs and supply and demand take care of itself.
Of course being as this is elite we are talking about you could procedurally generate the npcs their actions needs and associations. The planets political designation could determine the proportion of wealthy to poor npcs the number of potentially violent npcs etc etc.
Although for some "hard coded" missions, or static points of interest you may want a database of npc's you could have a large entirely procedural population interacting and creating missions around you, you may even witness the murder that creates a bounty yourself! or you may be the murderer!
In order to keep this system sane in terms of processor useage what you do is have a "range" of the player in which these events are worked out in diferent levels of details.
Say you land at a planet, the planets procedural generation has already assigned the planet regions, cities and districts, each with its population figures and "archetypes", to create wealthy and poor areas, crime rates and types and business numbers and types. Based upon these figures a calculation is made for how many "missions" are being generated AND fulfilled in each area of the planet - maybe names are assigned to these happenings for the purpose of news reports etc "keith smith murdered" "assailant unknown".
The city you land at then procedurally "fleshs" out this information by taking the missions and then distributing them around the region in which you land. More murders or assaults in assigned "rough districts" for example, more trading needs assigned to business districts. Still no individual npc behaviours are needed the system just knows that Keith Smith was murdered and has assigned the unkown assailant a name "Alan Jones" and assignes the crime to one of the areas determined by probability, as you travel around the city the area immedeatly around you is "fleshed out" further.
For the district you are currently in, unique npc level AI is procedurally generated to fit the districts already generated "profile" and additionally the missions, For example the system creates "Alan Jones" a known narcotics offender with 5 credits and needing a hit (just an example the game can pick from and combine form many possiblities). BUT it runs no scripts. It just assigns him (and all npcs) a location (simple x,y,z) and probability of him mugging someone again. if the dice roll comes up for him to mug someone the probability of who he mugs and being seen and if so who by is all worked out through simplified rolls based upon "nearby" npcs. NOTE the maths has no idea about the actual world its purely mathematical work. This happens in "real time" But no "behaviour" is being ran its all just maths.
Local police will be on the case, represented by a simple probability of catching the criminal etc etc. At the district level of detail, the current missions have all been assigned to the individual AI to represent "stuff thats occured before you arrived". The case of alan jones is being generated in real time to give a "live" world - missions actually being generated in real time, it gives an illusion of a living breathing world, theres a past - statistical and assigned to npcs as you arrive in the district, theres a present being generated mathmatically over a large area.
Finally theres the "detail" only being worked out within video rendered distance. As you move around the district the system takes the mathematical npcs (with xyz coordinates) and for those within render range pops them into "full on" npcs, using full AI, At this point they go from statistical to processing needs and trying to fulfill those needs so Mr Alan Jones may be trying to score his hit, whilst laying low from the police etc etc. Not only does it give you a chance to interact with events from the "local news" but because of the "live" nature of the district events can happen WHILST you are around, you may witness Mr Jones next mugging, or a murder by a procedurally generated npc or Mr Jones being arrested by the police or being terminated by an assassin etc etc.
This gives the player the "chance" to see incidents that they can work on later as a mission or they can "intervene"