Just for a little perspective, the thing that keeps NPCs from being usable isn’t specifically the AI, there’s a lot of issues with basically all the NPC handling code, in particular item handling is very badly broken which is what causes the “NPC eats a lighter” errors and a bunch of the crashes. I’ve tracked down at least a few of the things contributing to it, but had to shelve it for the current release because fixing it requires a large overhaul of the PC/NPC inventory system (they both use the same inventory system) which would risk making the player inventory more unstable in order to try and fix the NPC issues. Not a good tradeoff.
Even if we went to a system where NPCs didn’t do anything on their own except follow the player around, these inventory issues would still be present.
The REAL problem is that we need a developer that has the time, interest, and skills necessary to dig in, understand how NPCs work, and put in a lot of work to either fix or replace them. I have the skills, but I’m extremely short on time, and somewhat lacking in interest. Right now everyone else is in a similar state. When that changes, improvements can happen very fast, but until then, progress is going to be slow.