There's a very big difference. It's a neat way of providing a simulacra of curated gameplay in a procedural world without having to go full Elder Scrolls. It would help onboard players to game concepts and roles, drive engagement, add interest and texture for long term players --- and it takes absolutely nothing away from anyone else who doesn't want to participate.At which point people will say (because the missions use procedural systems) all you did was say "pick up this package from a guy (kill him), deliver it through pirates (killing them) to someone and the package, being a bomb, kills them" .. all you did was put several things that are in the game already, together .. well, yeah! Meanwhile in the game now, Fuel Rats is a quest, recording barkmound sounds, is a quest, undermining a power is a long term quest. There's no difference.
I'm sure that Frontier could prototype a procedural, chaining mission system capable of many thousands of permutations (including activities, rewards, risks, wrinkles, etc) -- without having to add much (or anything) to the game in terms of systems or other fantasy requests.
You could quite literally paper-prototype this yourself with a flow chart and a few decks of cards.