I would have to say Cata. It irreversibly (at the time, at least) removed quite a lot of ‘classic’ content. For example, the Defias were almost completely replaced by simple thugs. Zones were changed and there was no way to get back to the original versions that I liked. It was, ironically, a cataclysm for us players.
Strong second would be SL, just for it’s poor execution and almost impossible to follow story.
WOD overall worst
SL, honorable mention. Everything was so detached, the story got so convoluted I just stopped paying attention, so many currencies and reps. oy vey
Yeah, the evil twin did it. That’s what I said
Cheap writing trope
That was the exact same “trope” that was used when Arthas raised Sylvanas a banshee queen.
So was that bad writing as well?
Cataclysm.
#1 WoD - phone game tier
#2 SL -Covenants, Korthia, Jailer
#3 TBC
Warlords remains the worst. Introduction of pathfinder, a twitter integration full patch, cut content, a terrible launch, in between Mists and Legion which are still among the best.
WoD was, is and always shall be the worst expac. Even Hello Kitty: Adventure Island was a better WoW expac. Garrisons ans the token were the only redeeming features from that fiasco. 
No because it wasn’t retrofitted onto the end of the story to justify an alternate ending. It was part of the story all along.
That’s why Zovaal as a whole is regarded as such a poor villain. They claim he’s been there all along and responsible for everything, and yet there’s ZERO trace of it until they twisted and disjointed his story to fit it in after the fact.
Poor writing is poor
That’s true of any afterlife. Even if by chance one religion gets it right, all the others would be wrong and would be shocked and amazed at the power that was controlling them when they knew nothing about it.
Where is there any description of the Azeroth afterlife that is contradicted by SL?
I wanna say legion for what they did to survival hunter but I played WoD so going with WoD as one, SL for two, three will be BFA , four has to be MoP with the removal of talent trees and five would be legion for what they did to survival hunter.
6-17-2024 -
NONE!
I love WoW! There were NO “bad or worst” expansions in WoW! They were all awesome. However, my all time favorite WoW expansions are: Wrath of the Lich King, Legion and Shadowlands.
Cheers! - JJ -
Of course the guy named Nosferatu thinks this. Virtual Boy Ravenloft from Wish. com 
Please have mercy on my optic nerves.
Suramar was pretty tough, first time rolling through in questing gear. It got easier as you geared up, and by the end of Legion it wasn’t hard at all.
Shadowlands had pretty good dungeons, Nathria is one of the best raids even, imo, but it’s too heavily bogged down by the patches and systems that only serve to hamper player progression in the name of retention.
Rolled the same conduit on a raid boss for the fifth week in a row? Congrats, you lost your gear roll for that week. Want to progress some cosmetics in your off time? Better clear your calendar, all of the cosmetic tracks take ages. Legendary? Hahaha, your weekend is gone, here’s Torghast. If you want to hyper optimize run around the Maw for a month with no mount to get jewel slots!
It’s a shame, but from a purely gameplay oriented standpoint Shadowlands takes the cake, and it’s not even close. Then you get into story/theming/korthia.
The leveling experience is also by far the slowest of all xpacs. It’s just so exposition heavy because the narrative is so confusing and unintuitive compared to the rest of WoW.
I know we are discussing expansions , but the worst version of wow for me is hands down vanilla wow . I tried leveling a toon multiple times and each time couldn’t get myself to level above 30. what a drag of a gameplay
I always have to give the same response to this question.
WoD: What was there was fun to do. The main issue was that there just was not much there. A lot was cut. So unless you regularly raided, there was very little going on.
Shadowlands: There was a lot of things there to do. The problem was that a lot of it was just not very fun to do. There were too many barriers put in place of gameplay. In many cases the game actively fought against the player’s fun. And the devs just didnt listen to the community.
We said, dont lock covenants. They did.
We said conduit energy was a bad idea. It was.
We said not having mounts in the maw was unfun. It was.
We said dont tie a grind to Torghast and have it be an endless run for rewards. They tied a grind to it and made it unfun.
They didnt iterate on anima powers in Torghast. Some specs were a blast to play. Others were miserable, unless you got the one good one early in the run.
Korthia. Thats it. It was such a small, miserable and horrible zone with grinds.
Both were bad for different reasons. But Shadowlands wins the crown for me. During WoD, I would just play other games when it wasnt a raid night, or level an alt. Shadowlands, I would log in sometimes, then look at the chore list. Sigh and log out. Not because I was bored. It was because those aspects of the game were just not fun.
WoD. It is and forever will be the worst expansion, because blizzard tried to do a bunch of stuff that they thought would be “for the good of the game”, and blew it due to extreme hubris.
You think you do, but you don’t
—J. Allen Brack, WoD Blizzcon
Mythic raid size. Breaking Demo warlock. Flying/pathfinder. Time travel story. The selfie patch. Mission tables. Raid or die. You know it’s bad when garrisons are the best part of the entire expansion.
They really thought people wouldn’t leave. Like they could do no wrong.
It depends on how you define worse. Imo, either Cataclysm or WoD did more long-term damage and set some truly horrendous precedents. If we ignore how each expansion represented a change in design philosophy going forward, and instead view each in a vacuum, the title of worst goes to Shadowlands, easily.
Either way, Blizzard still owes me a handwritten, formal apology for the following:
-Cataclysm
-WoD
-BfA
-Shadowlands
(Didn’t play DF, can’t comment.)
um, probably WoD? shadowlands season 1 and 2 - but shadowlands season 3 and 4 was great