This patch features a whole range of optimisations targeting the performance of villager AI. As the number of experiences, knowledge, and other details about a villager grows, it takes longer for them to think it all through. In the late game, this was especially noticable when you start having 30-50+ villagers and play for many hours. This update drastically speeds up the slowest parts of this thinking, resulting in much much faster conversation responses, quests, and overall responsiveness in this late-game.
There are still some things to be aware of for these large towns. For instance, when a new villager would like to join your village, it can take some time to properly generate all their details and fit them into the existing large data store. Likewise, when you first load a large save, it can take some time for all villagers to decide what they are doing (since this happens all at once right now). However, in both cases, after these situations pass, the villager AI performance tends to return back to normal performance.
Of course, there is still a lot of potential for improvement, and I definitely have ideas for even further optimisations. These will definitely come in the future too!
PS: We are also working on other exciting things behind-the-scenes - stay tuned!