This is that kind of feature players shly imply to be fed with, like an unexpected gift from your friend that you appreciate, only for WoW players its that kind of gift people have tiny orgasm with when announced at blizzcons, I will say the same for this because people even had "tiny orgasm" when scenarios were announced at blizzcon which isn't really that great.
Simlar to Deathwings [Stood in the Fire], Freak Occurrences will be rare turbulence to add danger and spontaneousness around Azeroth. From common everyday crimes of thieves and bandits, lightning and meteor or the spotting of a mythical creature, the citizens of Azeroth will be wakened.
Mob based turbulence such as thieves and bandits will spawn in specific spots in the world and stay there until they decide(by random or by schedule) or mobilize and return to the same place or move to their camb B once they have finished their task, or unless of course they die in action. They do not reset like other mobs, they just recover their health slowly.
These Mobs have the power to kill guards and players, but they will not be able to kill quest givers and vendors or any sort of service provider. They will be able to attack them but they can only be brought down to 1% and are still commutable, they will be displayed as injured (laying down dead) to display their injuriny and they will recover in just minutes.
Thieves: They will spawn in hideouts and depending on how skilled the thief is the harder and farther away his hideout will be. Thieves will be seen running in and out of shops, banks, and treasuries, carrying a sack of gold in their hand or a sacred artifacts or even a painting. Thieves will not try to attack players but will attempt to flee back to his hide out. Some will be on foot, some will be sprinting, some will be on normal mounts, some will be on flying mounts. They will not stop fleeing until they are down to 30%, it is up to players weather they return the stolen goods or not.
And what better way is there to unite the community than hunting down a thief?
Challengers: Every once in a while a great warrior of great power and cunning comes to town to take on all comers to test his skill and prove his prowess. He will not attack players or guards but accept challenges from solo, groups or raids, depending on how strong the challenger is.
Scouts: From Amani to Qiraji all factions have scouts. They can be seen Patrolling multiple zones or taking long trips from point A to B.
All scouts will be on mounts, some flying and some not. If they are spotted some will attack even if you are on your epic flyer. But what you need to watch out for are "speedy scouts", who do not attack players. Speedy scouts are couriers carrying messages travelling back and forth from point A to B. But they carry information your faction leaders would very handsomely pay for, though it will take patience and timing to kill them.
An example of a courier is a Zandalari troll on a very fast flying mount travelling between Zul'Aman and Zul'Gurub.
Spies: Agents of Espionage working for SI:7 or the Shattered Hand clan. They are amongst the innocent bystanders or pretending to be your local bread vendor. So you better watch out if anyone is acting odd, you never know when your being watched.
Lightning: Delivered by Thorim himself ( jk ). On very rare occasions lightning will hit a random player that isn't inside a building or anyone without proper shade above their head. This can only happen when its raining or when in Netherstorm. The lightning should kill instantly. People flying on a rainy weather are most vurnerable to lightning.
War-Party: A band of raiders from your local bandit base or a platoon or grunts from the Warsong Lumber Camp in Ashenvale, seeking harm to your village.
This turbulence will fullfill my fantasy of seeing those Kol'kar raiders attack Ogrimmar.
Assassins: Sneaky and evasive, assassins move around the terrain with ease and hardly detectable. They will use hit and run tactics on specified targets. They will run away as soon as they have killed a target with the same description they were given. Targets could go from level 85-90 gankers in STV or players who have their pet outs, all warlocks or all druids. It doesn't even have to be assassins it can just be a simple band of Pygmies trying to hunt down boars.
Mythical creatures: From Thorim in the park or the ghost of Aegwynn, some of these mythical creatures are malicious and some just decided to go for a stroll in the park. You could see Alexstraza fly by Stormwind or hear Bolvar yelling in Northrend or even see the body of Kael'thas washed up on south shore. These are very rare occurences.
What better way to brag than having screen shot of Kael'thas corpse? that's like seeing Osama corpse only for WoW.
Lore based epidemics: From leakage of the Forsaken plague from its factory or Worgen rabbis spreading like wild fire, or critters going berserk due to the Emerald nightmare. These are very rare events, they only last a day and could only happen twice a year at random dates.
Other tribulence may be: Story Tellers, Rexxar, Rare item Vendors, Fake Item vendors(grifta), a buffing priest or even four wheels of fury.
Also: if blizzard likes the idea, please don't just add this in Titan or expansion 6, its so simple and I dont want to have to wait another 4 years for such a thing, it will break my balls for sure.