Generally, when I play, I monitor the game using various addon tools. (Particularly, Dwarf Therapist.) When I note details about moodlets not fading, it is because I can still see them clearly as "in the last week" in Dwarf Therapist, despite many months passing in some cases without a refresher event. Obviously I cannot be assured that moodlets that happen in the last week are intended to last only one week, but it seems that many which should be temporary instead are permanent, long-lasting, or duration-resetting while they continue to stack and accumulate indefinitely.
I note the following, just off the top of my head, and I am willing to stream demonstrations of behavior as desired, as part of my Extra Life streams this year:
1. Dwarves often and regularly complain about "an absence of good food", in forts with 4000 lavish prepared food.
I understand that they might not get their best happiness from a roast of dwarven syrup when their favorite food is bumblebee brains, but I don't complain about a total absence of fine food when I ate a well-prepared steak instead of a well-prepared lobster. I might not be ecstatically happy, but I don't ignore the fine meal that I just ate enough to be UPSET about it. That's not just petty, it's childish, and unfun to manage, especially when there are so many foods which cannot be created because they cannot be created by dwarves or in kitchens at all.
2. Various negative thoughts (especially rain, and snow) appear to stack and not to fade off properly.
This results in dwarves which (eventually) cannot be made happy without resorting to outside tools and extreme interventions. Often, this appears to be minor events which possibly are getting their timer reset when they recur, as well as stacking. If 'caught in the rain' lasts a week, and on day 6 it happens again, it may be possible that the timer is reset to a week, but now with a stack of 2 "caught in rain" effects. Unless a dwarf is literally trapped in the rain indefinitely, this should not be as negative, long-lasting, or impactful as it is. I suspect that many moodlets are not set with the correct magnitude and duration.
3. Dwarven mood enhancers are not particularly effective, not particularly lasting, and do not seem to outweigh negative symptoms.
In a fort with thousands of prepared meals, smoothed bedrooms for everyone, a tavern for all, library, temple, and fine dining hall, dwarves are still not returning from a bad mood. While I recognize that dwarves should be able to experience a bad day while surrounded by opulence and family, this is a fantastic sea change from where dwarves were previously: A fine fortress yielded ecstatic dwarves that could watch fifty of their closest relatives cut down without an eyeblink. An average fortress would still yield happy dwarves, but their emotional state would be less resilient to losses and tragedy.
Today, a fine fortress yields mediocre-to-failing mood, with depression and broken dwarves always just around the corner with a bad raid or siege fight that adds more stressors. A rude, ragged fortress would be impossible to run: It would break down under the weight of its own psychological failings in short order. I shudder to think of players who enjoyed trying to secure macabre or fell moods by manipulating dwarven moods, as this seems like it would be an exercise in folly today.
4. Socialization appears to be lacking as a dwarven stress reducer.
Dwarves dance around in the tavern, but only converse in narrow circumstances, leading to insufficient socialization. This often breaks the positive impacts of friendships, romances and marriages and more. Dwarves should not need to be adjacent to speak, or their AI should drive them to clump into tighter groups in order to do so correctly. See also, issue 6, below. Dining halls/meeting halls that used to be full of dwarves are now empty, barren cafeterias where dwarves scarf down a meal before returning to the tavern.
5. Multiple-servings-per-round Alcohol poisoning in taverns results in not assigning tavern keepers, reducing the effectiveness of taverns in reducing mood impacts and negativity.
This cannot be allowed to continue, or taverns are going to remain less effective at addressing mood - dwarves get a positive moodlet for inebriation, but cannot reliably become inebriated without risking alcohol poisonings.
6. Dwarves complain about being away from family in situations where they've moved into a fort that is now at population cap.
This is resulting in the need for players to evict these dwarves, as they can never meet this happiness need, and will become more and more upset over time. This is a metagame consideration which requires the player to take in-game actions to work around PC/metagame limits and not to act as befits their dwarves. We cannot have 500 population in our forts and not melt our PCs. Dwarven happiness must not hinge upon restrictions placed upon the player by hardware/software limits.
7. Temples to "no specific deity" are not accepted by various members of the dwarven community. As with the "prepared meals" issue, a lesser temple might not be enough to keep a dwarf happy indefinitely, but it should still suffice to meet the labor/need to pray and get the dwarf back to work. "Overlapping temples" should be an exploit, not a requirement.
8. Dwarven mood enhancers often seem to involve a far greater deal of micromanagement than is fun or enjoyable.
To use an analogy, the current version is like playing Stationeers - a game where you are forced to micromanage which items you are actively holding in each hand (and in each of twenty pockets) while swapping parts, tools, and devices - while the previous version was like playing Space Engineers (place blocks, weld, enjoy). To wit: Dwarves complain about not performing a craft, not being in a fight recently, not being able to practice a military skill, not being able to converse or fraternize. This alone is fine, stress at unmet needs is fine. While obviously a dwarf cannot do all of these at once, dwarves which are placed into a one-month-on, two-months-off militia schedule often still seem to have difficulty meeting these needs on their own, implying that their met needs are not lasting sufficiently long to allow dwarves to transition from militia to civilian without being trapped in a slow-burn quagmire of unmet needs slowly dragging them down.
It should not be required of the player to micromanage dwarven labors in order to provide additional free time for dwarves who need it to pray, study, or drink in the tavern. Dwarves should be adept at meeting their own needs, not cluelessly willing to work until madness. It should not be expected of a player to be constantly flipping labors on and off of various dwarves to keep them satisfied. This results in spending far too much time poring over dwarven emotions and needs, and nearly none left to do anything else at all. (You know, like playing the game.)
9. Generally, dwarves seem poor at meeting their needs or keeping their needs met.
If dwarven needs are expected to play such a powerful role in their behavior, then it would be wise to draw a page from Rimworld: If a need is so extreme as to devolve into dwarven madness, then the dwarf should cease performing duties and roles other than those required to MEET THAT NEED. If an absence of socialization is sending a dwarf around the bend, why are they still operating that pump? Dwarves abandon jobs for starvation, thirst, and other physical ailments. If the intent is to make mental/social/psychological/spiritual needs on the same levels as those that are physcial, then dwarves need to abandon labor for needs - period.
I would have to formulate more detailed observations, but it does not seem to me that stress is "fine". I cannot imagine stress working correctly if one were to take over the management of an existing dwarven hamlet in fortress mode and then just let it run for any length of time - between increased travel time and reduced efficiency of layout, this sounds like a recipe for a total emotional meltdown over a long enough timeline, and 'long enough' would seem to be fairly short, in my experience.