Proc gen has massive potential, but where it's being used for simulation and realism there is a problem IMHO - realism itself is no guarantee of drama: after all real life probably doesn't work this way.
But that's fine ... It's going to get very boring, very quickly if you can break the game down to:
1. Buy stuff
2. Enter hyperspace
3. Fight something
4. Dock
5. Sell stuff
6. Back to step 1
That was the original Elite, groundbreaking as it was - it wouldn't do in 2012. If you're guaranteed to get attacked every mission, you're expecting it for starters, and then it feels scripted. Space is big and getting attacked should only be a part of what might happen (with the chances getting higher in different situations ie, busier trade routes with less police protection).
What if I want to be able to switch out a couple of missiles or detach my lasers to squeeze in an extra 5t of cargo for something I know *should* be safe? Then I have to run like hell when I do have that chance encounter?
The next thing to avoid is too much 'levelling' the enemy ships to yours. Since here, the player won't be the centre of the universe, I should expect everything else in it (AI included) to be going about its own business. It would come down to 'encounters' in space, which would play out differently depending on:
1. What have you encountered - what are its broad goals?
This comes down to whether you encountered a career pirate, trader, miner etc. They'd all have different basic (but interchangeable) behaviors. A pirate desires to take cargo from other ships, a trader desires to move cargo from point to point, a miner desires to find asteroids or salvage. There might be other types too such as a bounty hunter, like a pirate but that only attacks criminals. Step 1 determines what choices it faces when it meets your ship.
2. What are it's immediate goals?
This is all about what it wants to do right now. We know it's a pirate, for instance - but perhaps its all pirated out and has no cargo space left? Why would it risk an attack? Perhaps its heavily damaged? On the other hand, maybe its brand new, fresh out of space dock and looking for something to steal.
3. What does it think about the encounter?
So by now, we've established that we've encountered a pirate ship, that its empty, in a good state of repair, and it wants to find cargo to steal. It encounters you. Is it a guaranteed fight? No. What does it think about you in relation to achieving its goals? Are you stronger than it? A more skilled (elite rating) pilot? Are you in a group? Is he? Are the police likely to intervene here? Does he have a cargo scanner? Are you carrying any cargo? Is it valuable? etc etc etc.
So there's ample scope for encountering the wrong people, but at the right time, and since you have own choices to make - you might both choose to fight, to run, or one chases the other, etc - keeps it different.
And then throw in other encounters like asteroid fields and the like. It's possible that you might get attacked by a mining ship if it decides you're stealing what it thinks is his (a nearby asteroid), or a trader if it happens to think you're weak, it can get away with it, or its just had a few bad missions and is losing money, etc etc.