excluding end bosses, what do you consider to be the hardest encounter in each raid?

[silmarilen]

Good for your guild. Not everyone has the same experience? I mean, someone on here put Mother has the hardest for them which is a lot weirder to me then those of us that put Zul.

I think Zul is harder than Mythrax (which is the other most common listing), and it's certainly a lot more particular about comp. Maybe it's easy if you have the ideal roster but if you don't, it is a pain in the ass. I am in two raids and even in the group that had the ideal classes/races, it was still the fight that had the most wipes.

When I said mythrax I ment pre-nerf mythrax. Post nerf it's one of the easier bosses in the tier imo. Same with baleroc, before it got nerfed it was undoubtedly the hardest boss in the raid other than ragnaros, but after it got nerfed it became a lot easier and that's why people are mentioning other bosses. My guild at the time spent a month progressing on baleroc and then killed staghelm in ~10 pulls (http://puu.sh/CkFFZ/e0f45aecea.png), yet there are people here who think staghelm was harder because they only reached baleroc after the nerfs.

[Greyvax]

I did all of these as current, so i'm going to list the bosses that were ALWAYS cockblocks for an average guild

Molten Core: Baron Geddon
Blackwing Lair: Vaelastrasz
Zul'Gurub: Tiger
AQ20: The guy where you break the shell
AQ40: Twin Emperors
Old Naxx: Four Horsemen

Karazhan: Netherspite
SSC: The Lurker Below
Tempest Keep: Al'ar
Mount Hyjal: Rage Winterchill
Black Temple: Mother Shahraz
Sunwell Plateau: Mu'ru

Naxxramas: Grobbulus
Ulduar: Mimiron
TotC: Twin Val'kyr
Icecrown Citadel: Sindragosa

Blackwing Descent: Atramedes
Bastion of Twilight: Valiona & Theralion
Firelands: Beth'Tilac
Dragon Soul: Spine of Deathwing

Mogu'Shan Vaults: Elegon
Heart of Fear: Garalon
Terrace of Endless Spring: None, they were all easy except for Sha
Throne of Thunder: Dark Animus
Siege of Orgrimmar: Siegecrafter Blackfuse

Highmaul: Ko'ragh
Blackrock Foundry: Blast Furnace
Hellfire Citadel: Socrethar

Emerald Nightmare: Cenarius
Trial of Valor: Odyn
Nighthold: High Botanist
Tomb of Sargeras: Fallen Avatar
Antorus: Kin'garoth

Uldir: Mythrax

[Waltzinblack]

I progressed through all these raids when it was current.

Molten Core: Garr
Blackwing Lair: Firemaw
Zul'Gurub: Jin'do the Hexer by far.
AQ20: General Rajaxx, the 2nd boss lol.
AQ40: Twin Emps
Old Naxx: Four Horsemen

Karazhan: Shade of Aran
SSC: Morogrim Tidewalker
Tempest Keep: A'lar
Mount Hyjal: Azgalor
Black Temple: Illidari Council
Sunwell Plateau: M'uru, and it isnt even close.

Naxxramas: Thaddius
Ulduar: Firefighter Mimiron
TotC: None.
Icecrown Citadel: Professor Putricide

Blackwing Descent: Heroic Chimeron 25
Bastion of Twilight: Heroic Cho'gall 25
Firelands: Heroic Rhyolith 25
Dragon Soul: Heroic Spine of Deathwing 25

Mogu'Shan Vaults: Spirit Kings... trying to get the right spawn order... lol.
Heart of Fear: Amber-Shaper Unsok
Terrace of Endless Spring: None
Throne of Thunder: Heroic Dark Animus 25
Siege of Orgrimmar: Heroic Paragons of the Klaxxi 25

Highmaul: Enduring it. Really this is the worst raid ever made by far.
Blackrock Foundry: Mythic Blast Furnace
Hellfire Citadel: Mythic Magtheridon

Emerald Nightmare: Mythic Cenarius
Trial of Valor: Mythic Guarm
Nighthold: Mythic Star Auger
Tomb of Sargeras: Mythic Fallen Avatar
Antorus: Mythic Aggramar

Uldir: Mythic Zul, or enduring such a shit tier.

Ignoring that the thread title said "excluding end bosses"...
What the hell was wrong with Highmaul? I loved it. There have been far worse raids.

[Drunter]

Karazhan: Netherspite (excluding Prince & Nightbane)
SSC: Leotheras
Tempest Keep: Al'ar
Mount Hyjal: Azgalor
Black Temple: Gorefiend (lol constructs)
Sunwell Plateau: Mu'ru

Naxxramas: -
Ulduar: Mimiron (25H)
TotC: Twin Valks (25H)
Icecrown Citadel: Professor Putricide (25H; before the zone buff hit ~15% and made him pretty trivial)

Blackwing Descent: Maloriak (25H)
Bastion of Twilight: Council (25H)
Firelands: Baleroc (25H)
Dragon Soul: Spine (25H)

Mogu'Shan Vaults: Elegon (25H)
Heart of Fear: Amber Shaper (25H)
Terrace of Endless Spring: Lei Shi (25H)
Throne of Thunder: Dark Animus (25H)
Siege of Orgrimmar: Siegecrafter (25H; before the nerfs made it trivial)

Highmaul: Koragh (M)
Blackrock Foundry: Blast Furnace (M)
Hellfire Citadel: Gorefiend (M)

Emerald Nightmare: Eyeball Tree ilglklgknoth (M)
Trial of Valor: Odyn (M)
Nighthold: Star Augur (M)
Tomb of Sargeras: Mistress Sasszine (M)
Antorus: Aggramar (M)

Uldir: Fetid (M)

[Kuruption]

(these are just form my experience)

Molten Core: Baron Geddon because people couldn't figure out if they were the bomb
Blackwing Lair: Vael (killed a couple of guilds I was in)
Zul'Gurub: Hardly remember this raid
AQ20: The 2nd boss (I just remember taking forever on this boss)
AQ40: Twin Emps (didn't do when current, but I heard it was awful)
Old Naxx: Saph (didn't do when current, but I remember Saph being a pain during BC)

Karazhan: Shade of Aran (guess it's hard to stop moving)
SSC: Leo just because I was a healer and dpsing your shadow was rough
Tempest Keep: A'lar
Mount Hyjal: The guy before Archimonde (they were all pretty easy)
Black Temple: Gorefiend, in case you had people who didn't know how to play that game
Sunwell Plateau: Guild only made it to Felmyst, but heard Muru was the roadblock

Naxxramas: Thaddius, because people had problems figuring out their debuffs somehow
Ulduar: Mimiron
TotC: The PVP fight
Icecrown Citadel: Professor (great fight)

Blackwing Descent: Chimaeron
Bastion of Twilight: Council
Firelands: Shannox, because we had people who didn't know how to kite
Dragon Soul: Spine

Mogu'Shan Vaults: Elegon
Heart of Fear: Garalon because people would always sit in his circle (first boss on heroic was bad too because of the RNG on which platform he took)
Terrace of Endless Spring: Lei Shi because of how annoying it was
Throne of Thunder: Animus (Durumu close 2nd)
Siege of Orgrimmar: Paragon/Blackfuse

Highmaul: Twins
Blackrock Foundry: Furnace because it was such a cluster
Hellfire Citadel: Gorefiend

Emerald Nightmare: The tree
Trial of Valor: Odin
Nighthold: Star Auger
Tomb of Sargeras: Avatar
Antorus: Aggramar

Uldir: Zul

[Deleted]

The 19 other guys in my raid

[Mashanerz]

Molten Core: Sulfuron because the god damn heals when you raid with scrubs makes it a 30 minute fight.
Blackwing Lair: I hated Razorgore, the kiting and DPS requirements, a lot of autonomy among a 40 man raid.
Zul'Gurub: I didn't do much of this because I was a "real" raider doing 40 mans not casual mode BS, Mandokir was too fun even if he had snowball mechanics that could quickly get out of control.
AQ20: Buru, required awareness of your group that can be a problem
AQ40: Twin Emp's, one of the hardest bosses in vanilla
Old Naxx: Anyone that doesn't say 4H is a liar....but also Razuvious for his fun and unique encounters....LoS mana drain? MC tanks? Fun stuff.

Karazhan: Shade of Aran. All the other 'difficult' boss fights were optional and the random nature of Malchezaar doesn't matter for this list
SSC: Leotheras, his WW just followed me around.
Tempest Keep: Solarian, no question. Reaver was a joke and A'lar was reasonably difficult, Solarian wasn't fair.
Mount Hyjal: Azgalor...that enrage timer tho
Black Temple: Reliquary, hate it right in it's stupid face(s)
Sunwell Plateau: Muru was the last boss in this instance right? Felt like it.

Naxxramas: Fun fact, this instance is a joke for 10/25
Ulduar: Mimiron, especially if you hit the button....because I assume both Yogg and Algalon count as the last boss
TotC: This raid was forgettable....the PvP one?
Icecrown Citadel: Lana'thel, but I think a lot of the bosses were similar in difficulty

Blackwing Descent: Maloriak...I hate RNG in my encounters
Bastion of Twilight: Valiona/Theralion because the swapping could get very hectic, especially if your bad players got hit.
Firelands: Rhyolith because his legs had a tendancy to be very WTF sometimes
Dragon Soul: Spine of worst raid boss ever

Dragonsoul was so bad I quit the game and didn't come back until HFC was released and holy crap was that a fun raid.

Hellfire Citadel: So this one is a tie, Iskaar was aids without the add-on and Xhul was aids because most people didn't understand the actual purple/green mechanic

Emerald Nightmare: Il'gynoth, because it was hard on my vocal cords yelling at folks "NO, KILL IT NEAR THE FUCKING EYE"
Trial of Valor: I guess guarm because Odyn was a joke? But so was guarm
Nighthold: star augur was aids
Tomb of Sargeras: Mistress was meh
Antorus: Coven because the switching was a bit much for some folks

Uldir: MOTHER because of all the stupid bugs. I would be the tank for the adds, not cast a single spell or ability, and end up with 110% threat on her and that's not even the only bug in there.