The Unsoloable: Legion Edition
Mythic Ursoc hits so damn hard. I think my best attempt was at ilevel 410, and I got him down to 84 percent or so. This WILL be soloable eventually, via improved gear, but it might be closer to the end of BFA.
Dragons of Nightmare (Mythic)
At 90 percent health, the Dragons spawn a Lumbering Mindgorger behind one of the portals in the arena. The Mindgorger will channel Devour Nightmare for 80 seconds, upon which he will instantly wipe the raid. Since you can’t enter the portals while soloing, this means you have 80 seconds to defeat the Dragons before you’re dead. This interacts painfully with the Slumbering Nightmare effect, which WILL put you to sleep for 30 seconds during the Devour Nightmare cast. Thus, the DPS requirement is incredibly high and pretty much unattainable by a Protection Warrior for the time being.
Trial of Valor (Mythic)
All bosses, probably
This is pure speculation, because I LOATHE this raid, but I’m guessing Mythic ToV is unsoloable based entirely on the difficulty I’ve had soloing the place on Heroic (which I’ve done, barely).
Undetermined. I’ve been able to solo four Mythic bosses so far, and the ones I’ve failed at feel more like large gear checks rather than mechanical impossibilities.
Tomb of Sargeras (Mythic)
Undetermined. I can’t get past Mythic Goroth, so my efforts are a bit lacking thus far. I’m guessing there will be mechanical problems preventing soloing of the later bosses (Desolate Host, Maiden, Avatar, Kil’jaeden), but the earlier foes might be killable with decent gear.
Imonar the Soulhunter (all difficulties)
Sleep Canisters. Why’d it have to be Sleep Canisters? Once you get hit by your first Canister, you’re done. Why? Because you can’t avoid the Canister, which puts you to sleep for 12 seconds, plus another 8 seconds when it wears off and you get hit by the resulting Slumber Gas. You’ll get hit by another Canister before the Gas wears off, so you’re basically sleep-locked until Imonar manages to kill you. I don’t see this fight ever being soloable unless Blizzard makes mechanical changes to the Sleep Canister ability.
Coven of Shivarra (all difficulties)
Remember the Odyn fight in Trial of Valor, and the annoying Hymdall/Hyrja interaction? The Coven have a similar problem, thanks to Shivan Pact; unlike the Odyn fight, the Coven don’t do any long spell casts that allow you to split them up long enough to do any damage (Touch of Darkness is too short, and it only happens when Asara is active). Even if they did, they have a health pool at least an order of magnitude greater than the shielded Valarjar, PLUS all of the Titan torment phases, so it doesn’t seem soloable unless the Pact ability is either nerfed or removed.
Essence of Eonar (all difficulties)
I’m POSITIVE that this fight can’t be soloed on Mythic, due to the spaceship phase (hell, even large groups still have trouble doing this version of the fight). On lesser difficulties, I’m not 100 percent sure, but it certainly SEEMS unsoloable. The need to be in multiple places at once, plus waves of ranged mobs (damned bats), looks to be insurmountable for a melee class. I’d be happy to be proven wrong!