A lot of this may come down to how much they wish to place on the shoulders of NPCs vs human players.
If human players work up to most positions of power, the pressure on the engine reduces. Humans will actively spot problems and raise bounties themselves. NPCs with the right skills or characters may then fulfill those bounties, as may players.
This is something I've been wondering for a while. In terms of "rope bridge" designs, you would expect that behavioural design may start off relatively simple. You effectively build a set of measures and methods that are available.
If the "world preview" includes something akin to a prologue with stationary or minimal functionality NPCs, they could potentially employ an unwitting userbase who are developing their OPC scripts to effectively develop NPC scripts and generic community scripts, optimising development resource usage.
Following on from that, the higher you move up the "chain" in regards to aristocracy, nobility and royalty, the more specialist your duties potentially become. There functionality becomes increasingly dependant on more input, assuming it's going to function well. They have said however that players will outstrip NPCs on those fronts, so perhaps that's less of a worry.
If KoE sees a decent spread of players in roles, and remaining NPC roles are all but mopped up by it's conclusion, the duties of the engine and NPCs could safely be restricted to "individual function" rather than group and town management in all but the most simple cases etc.
Will human players raise bounties and generate quest content through their actions? Undoubtedly. Will NPCs? Individual content will no doubt raise bounties. Trade, theft, death, all examples of things that may trigger reaction.
Wider scale or more damaging events could be reacted to on a higher level, potentially tweaked by staff. We know there is a talent engine that might be utilised to redress balance between regions and create diversity.
Where intervention is required, they may simply decide to code in reactive rules there and then for future automation. That way, the engine is a growing constantly evolving system.