With Patch 10.2.7, Blizzard did some tweaking to Battle for Azeroth raids, making most encounters easier to solo on Mythic. The two big obstacles right now are Mythic N'zoth and Mythic G'huun.
Note that both N'zoth and G'huun can be killed solo on Mythic under extreme circumstances like Arcane Mage burst attacks, but that isn't feasible for 99% of players.
Uldir
You can now solo Mythic Mythrax, but Mythic G’huun still seems like an issue.
- Mythrax
Oblivion Sphere is no longer cast - Critical Mass still happens but Phase 2 ends automatically.
G'huun
- Power Matrix no longer eventually roots the player
Unfortunately, it seems that you still need two dunks within a short duration to make G'huun vulnerable so this may not be soloable, but duo seems much easier.
Crucible of Storms
While soloable, Restless Cabal is challenging due to Promises of Power.
- Restless Cabal
Continues to be a challenging fight to solo, relying on ways to remove Promises of Power to avoid being one-shotted at the end of the fight.
Battle of Dazar'alor
Battle of Dazar'alor had many of its fights changed, allowing players to easily solo it in Mythic.
- Opulence
No longer gains Hoarded Power when it finishes casting Hoard Power.
Conclave
- Loa's Pact no longer activates
- Crawling Hex duration reduced to 5 sec (was 30 seconds)
King Rastakhan
- Zombie Dust Totem no longer Mind Controls players
Jaina
- Freezing Blood no longer triggers
You can DPS through Flash Freeze
Eternal Palace
The big issue in Eternal Palace was Queen's Court, with other bosses being already soloable.
- Queen’s Court
Separation of Power no longer activates
Ny'alotha
- Vexiona
No longer fear players with Terrifying Presence when she casts Heart of Darkness
N'zoth & Carapace
- You no longer get instantly Mind Controlled if you don't have Ashjra'kamas, Shroud of Resolve equipped
- N'zoth is still very tricky to solo, due to Sanity loss effects
- N'zoth fight seems to be broken with adds continuously
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