I feel like this is what people often miss.
I've played MMOs for roughly 25 years if you include MUDs I played as a kid in the 90s. Most big MMOs have great expansions, good expansions, and "that one stinker" (like, LITERALLY all of them have "that one stinker" - think of any MMO you've played and there's at least one that immediately pops into your head as "oh, yeah, Ren's right; THAT one...") with a few "meh" ones that were not really good but weren't bad and were enjoyable enough. The not-big MMOs simply never had great/good ones, or had so many stinkers that no one really remembers the great/good one that they might have had in the mix somewhere.
WoW had Warlords of Draenor, for example, and there is a long-standing trend of "every other expansion (after Wrath) sucks with the odd ones in between being good. Vanilla, Burning Crusade, and Wrath were considered good, Cata bad, Mists good, Warlords bad, Legion good, Battle for Azeroth bad, and then Shadowlands worse - this was stark enough it has forced a major course correction into Dragonflight, as I understand it (no longer play) because of both two stinkers in a row and HOW BAD Shadowlands was that it gave WoW the dubious "SECOND stinker" expansion.
But there's an interesting flip-side to this:
Even many of the GOOD expansions, or ones seen in retrospect as good, seemed bad at the time. It's part of the Human impulse to put more weight on the moment than the past/future and not see things in the moment with good context. Mists of Pandaria was seen as kind of bad by a lot of people at the time, but then looked back on fondly in retrospect. (It also had that fantastic moment with the ghost dude that I still remember to this day - "When I was young...when I was young....... I. WAS. EMPEROR.") Even BfA had a pretty amazing moment with Jaina's mother and her (since I had quit the game by then, I only saw this in a cutscene video on YouTube, but the music and mood there just hit all the right notes seeing Jaina's past and her mother's initial rejection of her and the music as her mother brushed through the illusion to save her daughter). Even Cataclysm seemed pretty bad at the time, but by Warlords, people were praising it. ...as I understand it, Warlords and Shadowlands have not gotten the rose tinted goggles treatment, meaning they were both stinkers.
FFXIV has honestly had it pretty good. The closest expansion we've had to "the stinker" was Stormblood, but now in retrospect, it's widely praised, especially the 4.1-4.55 patch content, despite being pretty widely panned at the time. People attacked Eureka (and to be fair, it has the 300% buff now which HAS made it far better) and Bozja (which has not) at the time, but now people are begging for that kind of content.
It's REALLY easy to gloss over the good in times of trouble, only to look on fondly later. This concept is so Human it exists as a famous literary stroke:
"It was the best of times. It was the worst of times."
...a famous line describing both how some people are happy while others are upset, but also serving a dual nature if you realize that even people under adversity have happiness and people in plenty have despair ("Ra-La will save us!")
Is an expansion good or bad? Well, it depends on who you ask. But more than that, it also depends on WHEN you ask.
SB was seen as terrible at the time but now people (especially people that liked the pre-ShB Healing and Tanking models) say it was the last good one. ShB was seen as fantastic at the time but this forum frequently derides it as "the beginning of the end" of sorts. Even though, at the time, the reverse was seen. Some times, this is a case of "different people", but sometimes, it absolutely is not. The "when" matters as much as the "who" of which the question is asked.
This.
Can't start a positive thread here without being attacked. And even if you start a negative thread, it has to be against the "right" negative thing.
Yes.
Not only does it attack ideas, but it attacks people, and often involves more heckling and complaining than "criticism" or "feedback". Moreover, there's just SO MUCH negative posting that it's gotten impossible to tell what actually needs to be done. It's like the boy who cried wolf; there are so many people complaining about the most inane of things or blowing things wildly out of proportion with hyperbole that any ACTUAL GOOD FEEDBACK (that is, actual criticism) is drowned out by the churning sea of salt.