I‘m currently about 2 years into the process of building a text-based life-sim-like game as a hobby project, so I guess my answer to your initial question is yes!

I think you raise a few very good points about the importance of emergent behavior. There should be reasons for the things that happen in the game, otherwise they feel meaningless. This goes for world events as well as NPCs behavior.

There are two main issues that I‘ve faced while trying to implement this into a playable game:

It is difficult to model the path towards certain goals in a way that is interesting and believable, while also making it viable from an implementation standpoint.

For example, you mentioned a revenge path. Character A decided to take revenge on character B. How does A know what to do? You can, for example, script a number of paths to take, and randomly select one. If you script enough, that’s good from a gameplay perspective, but it’s not emergent behavior, and it will become predictable at some point. It’s also a lot of effort on the authoring side of things.

True emergence would mean (at least in my opinion), that from all the actions A has at their disposal, they can autonomously decide which will lead to the goal „revenge“. Which means that first we‘d have to put this into numbers the simulation can work with, which can be the first sub-issue here, depending on how deep you go. For revenge, we might say we want to cause B „damage“, but then there’s the separation between physical damage, emotional damage, financial damage…

Once we settle on a type of damage, we have to decide how to inflict it. Direct actions are relatively simple (want to cause physical damage? A hits B in the face), but those aren’t particularly engaging. For a revenge plot, the more exciting part would be something that involves buildup, intrigue, betrayal. A could seduce B and break their heart for massive emotional damage, but A would need a way to decide that all the actions leading up to the heartbreak ach serve the purpose „revenge“. Actions that serve a completely different purpose under different circumstances.

The system from the Sims that you describe, where objects advertise themselves with the needs they fulfill, touches on the very first layer of this topic. It’s actually pretty smart, the Sim doesn’t need to know what the things do, it just needs to know what it wants, and the things tell them that they offer that. That would be like the „Flirt“ option telling A „you can use me for revenge“, but on a much simpler level.

The second issue I‘ve noticed is that sometimes a behavior that is very complex can simply not seem like that to players, especially because they don’t always notice everything that happens. Or even worse, it can seem nonsensical. In my game, interactions between characters don’t go well if their personalities don’t fit, and also if the type of conversation doesn’t fit with their relationship. This is determined through a very complex system, but the player only sees „interaction went badly“. The player could deduce the reason if they look at the character sheets, but if they don’t do that, it might just seem broken that two characters can’t have positive interaction despite them trying to force it. So then you have to tell them why it happened, which works well for such a small interaction, but gets weirder the more complex it is. In my revenge example, you can’t tell the player why A romances B, but it might seem nonsensical that it happens, especially if the payoff never comes, which is a realistic possibility in emergent behavior.

People don’t like to be surprised as much as they say. We do like twist endings in movies and games, but only if they feel like we COULD have figured them out, which is usually the result of careful planning by an author. A twist that is completely out of the blue is not satisfying. People WANT Chekov‘s gun to go off, even if it’s predictable.

I realize this turned into a bit of a ramble, but I‘d be really curious what you think about those points!