I only hated one.
Molten Core: Insanely boring, and frustrating, no mechanics to speak off, respawning trash, takes forever to complete.
Dragon Soul: Reduce, Reuse, Recycle. Great principle in waste management, terrible for end-of-expansion boss raid.
Blackwing Lair: Empty square boring rooms and uninspired fights.
I won't say ToC was bad because it had interesting fights and it was quick, which is a bonus. . AQ40 was a close contender for third place because of boring boss models and resistance stacking mechanics. It didn't get on the list because it had rather unique theme for that time in WoW and because C'Thun fight was pretty epic, even though very few got to see it.
---------- Post added 2012-12-01 at 06:23 PM ----------
The night is dark and full of terrors...
Copy/Paste, badly tuned. Nostalgia speaking here, but one of the most fresh and epic feeling raids (yes, it was too hard) became a sightseeing tour. Wasted potential, Naxx deserved better. Mechanics stayed fine, architecture didn't work for 10-man at all.
DS was bad, but remember hyjal? Uninteresting, easy bosses hidden behind walls of super annoying and extremely repetitive trash and stupid NPCs. The concept was completely broken (Archimonde was OK).
Copy/Paste, again. Illidan and Arthas were great villains, Deathwing didn't interest me at all.
Dragon Soul (Just because it was far to easy)
TOC gets the honorable mention. If possibly beats mags, except for the fact it was a single encounter dungeon.
And the worst raid ever title goes to...
Hard to choose, so many bad ones lately.
Dragon soul unrivaled victor obviously, along with all throne of the four winds and bastion of twilight. Yeah cataclysm was fairly weak on the raid front..
in no particular order:
1) Ruby Sanctum (one boss wtf)
2) Trial of the Crusader (what is this all about, one room and no sense of achievement what so ever)
3) Naxxramas 2.0 (after doing the 40 man version and stuggeling hard on it, this dungeon filled with watered down bosses was heartbreaking).
2 room dungeon for 4 bosses a pvp fight, and those god-damn long announcements. Really not what I enjoy about raiding. At least 1-room-1-boss dungeons are over with quickly once you get the place on farm.
2. Eye of Eternity
Purely because of how badly done phase 3 was. I was lucky enough to not encounter bugs such as "everyone falls through their dragons and dies at the start of phase 3" but I heard the cries of those that did. Flame Leviathan was much better.
3. Throne of the Four Winds
Same reason as EoE, but the bugs involving falling through the ramps happened less often.
3. Probably Ruby Sanctum (one boss filler content after 8 months of ICC lol...)
Also the ppl saying Naxx was watered down content are wrong. The biggest problem was the glyph system made every player extremely overpowered and if there was no glyph system at the time the raid would have been much more difficult
i swear... i think im the only one who likes ToC
Im going with
---------- Post added 2012-12-01 at 07:08 PM ----------
Hyjal makes DS look like the best raid of all time.
Seriously nothing is even 1/10th as bad as Hyjal.
1. Ulduar (I did love firefighter though, one amazing fight doesn't make a good raid though)
2. AQ40 (again, I loved Twin Emps, but overall it was bad, plus I hate bugs, Twin Emps is one of my all time fav boss fights though)
3. BoT (I just thought it was a very basic, rushed and badly planned raid instance, Cho'gall should of been far more epic, I also hated the design of the place)
It's weird that my top 2 worst instances have arguably my 2 favourite fights of all time, but one fight does not make an instance. My main pet hate is the design of the actual instance, not the boss fights.
Hated BC anyway.