As of last weekend I did the Rogue Assassination Artifact Quest Chain for the first time. I did it as Alliance and was like "How are we not revisiting this to deal with the aftermath later?!" I refer to Darkshire's Night Watch slaughtering the townsfolk and conspiring with The Legion to assassinate Anduin.
We need to revisit the fallout from that in particular because Darkshire is such an important quest hub pre and post Cataclysm. Ebonlocke is out there somewhere, as are the mayor and some councilmen . Plus we we have an Alliance town whose entire population was massacred. How can that not be followed up on?
That aside, here's a few other zones per faction that should be revisited for storyline updates:
Eastern Kingdoms
- Westfall/Duskwood/Redridge: We dealt with the Defias and Vanessa VanCleef is permantlly neutralized as a threat as of Legion. Due to Night Watch's actions in Legion, Duskwood is severely undermanned. Even worse, the Feral Worgen who prowled eastern and southwestern Duskwood have encroached on Westfall and Redridge. Not only that, they have been observed working with the the Gnolls in both regions to destabilize the region. Westfall and Redridge are trying to resecure their lands but their endgame is to ultimately make Duskwood secure again.
- Westfall: Gyran Stoutmantle has finally finished construction on Sentinel Hill. The Transients who flooded the region were given Moonbrook to settle and rebuild for the Alliance. In no time, a dock connecting Moonbrook to Feathermoon Stronghold in Feralas has been built and Night Elven settlers have begun to arrive. The Defias threat may be over but Feral Worgen who have crossed into Westfall from Duskwood have been observed working in tandem with the Gnolls to undermine the reconstruction efforts. Players travel across the region and ultimately into the Deadmines (Special version fo the dungeon) where they get the unexpected aid of a former enemy.
- Redridge Mountains: The Blackrock Orc threat from the Burning Steppes has been dealt with thanks in large part to the efforts of John J. Keeshan's relentless campaign. Colonel Troteman and Keeshan returned to Redridge after the campaign in Pandaria to rebuild Stonewatch and fortify the region. While the Alliance focused on the Legion, the Gnolls and remaining Orcs went into hiding, biding their time until the chance to strike back came. That chance came in the form of Feral Worgen from Duskwood. Players travel across the region to deal with old and new threats, ending in the rescue of a prize Night Elf taken hostage by the Gnolls.
- Duskwood: When word spread that Darkshire's Night Watch betrayed the Alliance and Azeroth by throwing their lot in with the legion, Westfall and Redridge moved to secure their boarders. With threats from within taken care of, Stoutmantle and Cononel Troteman enlist the assistence of Shandris Feathermoon and Vaness VanCleef to re-establish order in Darkshire, Rebuild Raven Hill and secure Duskwood. Players will first need to complete the questlines in Westfall and Redridge before they can quest in Duskwood.
- Hillsbrad (Alliance Side): With the blessing of Genn Greymane, Darius Crowley and former Horseman Thoras Thoradin have decided to cut a swath of destruction across the region to restablish an Alliance overland route from Stromgarde Keep to Gilneas. Durnholde Keep has already been taken and will be a staging point for the campaign. Players secure the keep, Route the Forsaken from Southshore and neutralize Tarren Hill as a threat.
- Hillsbrad (Horde Side): The Alliance Offensive was expected but swift and strong. Horde players will lead efforts to blunt the Alliance's momentum and keep them from retaking key settlements in Hillsbrad.
- Silverpine Forest (Alliance): Having succeeded in pushing into Silverpine, the Alliance has established a base at Amber Mill and already retaken Fenris Isle thanks to the fall of Lordaeron. The Forsaken remain a threat despite the loss of their capital and more so knowing how badly Gilneas wants to retake their homeland.
- Gilneas (Alliance): Having retaken the Greymane Wall, Genn and Tess leads their people into the heart of Gilneas City to restablish their homeland after years of exile. Both are in for the shock of their lives when they finally confront who Sylvanas chose to lead the Forsaken forces in Gilneas.
- Wetlands: The Tushi Pandaren have taken settled in the Wetlands, which is still has a share of danger. Players will assist Aysa Cloudsinger as she helps her people settle in their new land and deal with threats old and new.
- Western Plaguelands: The campaign against the Legion put a strain on the Argent Crusade and the reformed Knights of the Silver Hand. In the aftermath of the fall of Lordaeron, the Conclave is looking to relocate to the former Plaguelands. Remnants of the Scarlet Crusade and The Cult of the Damned fight for control of Andorhal in the aftermath of the fall of Lordaeron. To make matters worse, the Artifacts of the Conclave sent ahead have gone missing. Could there be a traitor?
- Eastern Plaguelands: Infiltrators have stolen the Artifact Weapons of the Ebon Blade and the Argent Crusade! Turalyon, Lady Liadrin and Vindicator Boros seek help recovering each artifact. Meanwhile, The Knights of the Ebon Blade seek heroes to help them in the purging the of the Undead forces that still remain in the Eastern Plaguelands.
- Badlands: With the Legion dealt with, The Earthen Ring and the Cenarion Circle work to mend the damage from the Cataclysm. The Horde has reinforced their position in the west while the Void Elves have built an outpost to the Southeast.
- Swamp of Sorrows (Alliance Only): Having routed Stonard, the Alliance moves to fully secure and reinforce their holdings while the Horde withdraws the last of their forces to The Blasted Lands.
- Blasted Lands: The Alliance and Horde forces have focused on rebuilding their strongolds in the aftermath of the Iron March Invasion. At the same time, they must deal with the demoralized remains of the Iron Horde who crossed into Azeroth and refuse to lay down their arms.
- Burning Steppes: The Thorium Brotherhood has completed construction of a powerful fortress in the middle of the region with the assistence of the Steamweedle Cartel. Moira Bronzebeard has come to petition the Thorium Brotherhood join the Alliance, Gallywix petitioning the Steamweedle to join the Horde.
Kalimdor
- Darkshore (Horde Only): The destruction of Teldrassil and the Horde's campaign through Ashenvale and Stonetalon Mountain forced the Night Elves to flee their homeland, now refugees under the protection of Stormwind. Having claimed the whole of Kalimdor for the Horde, plans are underway to rebuild both Auberdine and Lor'danel for the Horde. The region is far from secure as Night Elves and their allies harass the Horde at every opportunity in an effort to reclaim their homeland.
- Ashenvale (Alliance): The Horde's champaign in the west proved a respite for the Alliance Forces at Forest Run. As one of the few remaining Alliance strongholds in Northern Kalimdor, they were able to reinforce their position and taken the Warsong Lumber Camp to the South and Splintertree Post to the West. They are seeking help securing their new territory and push west to retake Astranaar.
- Ashenvale (Horde): The Horde's blitz through Astranaar and Darkshore left their rear flank exposed. Having lost Splintertree Post and the Warsong Lumber Camp in the East, the Horde digs in to blunt the Alliance's momentum and prevent any more loss of ground.
- Northern Barrens: The Highmountain Tauren have accepted the Horde's offer of land and have built and outpost to the west. The Quilboar continue to the Horde's supply routes but the timely arrival the Highmountain Tauren could be just the boost needed.
- Southern Barrens (Alliance): The Alliance has claimed Fort Triumph and Forward Command. The Earthen Ring recently erected bridges over the divide, providing access to the Northern Region for the first time since the Cataclysm. The Horde has heavily fortified all of the bridges to block the Alliance but there may still be a way through thanks to an unlikely presence.
- Southern Barrens (Horde): The Horde has rebuilt Camp Taurajo and The Great Gate is now open. The Horde has reinforced its outposts and more so now that the Earthen Ring has erected bridges to the Northern Region. The unexpected attacks by Grimtotem threatens to undermine efforts to secure the divide.
- Stonetalon Mouintain (Horde Only): The Huojin establish their first outpost on Kalimdor. Players will assist Ji Firepaw in the contstruction of two additional outposts and drive out the remnants the Alliance and Grimtotem forces in the region.
- Felwood: The Illidari have establised checkpoints to the north and south to purge the region of the Legion's taint once and for all. Behind them, the Cenarion Circle works to heal the region. There is unease within the Cenarion Circle due to the Horde's campaign in Ashenvale and Darkshore. Players must find a way to assist both factions deal with last remnants of the Legion.
- Desolace (Alliance): The fall of Teldrassil to the north has left Nijel's Point isolated deep in the heart of Kalimdor. They have moved operations to the recently captured Thunderaxe Fortress and a checkpoint at the Stonetalon Boarder. Reinforcements from Gnomeregan and Stormwind have arrived in Thargad's Camp to keep help keep the nearby Cenataur from cutting off the overland route to Feralas.
- Desolace (Horde): The Horde has redoubled their efforts to keep the Cenataur in line. Wary of the Alliance expansion to the north, the Horde seeks to complete a daring tunneling project that would link Desolace directly with Mulgore.
- Un'Goro Crater: It still remains one of the last untamed regions on Kalimdor. The Mag'har Orcs and the Lightforged Draenei both have plans for the region and a showdown between them is inevitable.
Outland
Overview: After the legion was neutralized on Azeroth, most of the Illidari returned to Outland to work with the Azerothian Forces there to deal with the demons still there and help find a way to stabilize the landmass. Meanwhile, The Earthen Ring and the Cenarion Expedition have made progress in their efforts to terraform the landmass.
- Hellfire Penninsula: After years of effort by the Cerarion Expedition, Vegetation has sprouted across the area that was once known as Tanaan Jungle. With it has come new dangers that must be dealt with.
- Terrokar Forest (Alliance Side): With word of the Legion's fall having reached Shattrath City, a massive rebuilding effort is now underway to restore the city. Outside the city, the Alliance mobilizes to as the last of the Fel Orcs prepares to make a final stand.
- Nagrand (Horde Side): Many years have passed since Garrosh Hellscream left for Azeroth. Once viewed as a hero, his name is now spoken of with contempt. Aggra has returned to her homeland to assist in renewed efforts to stabilize the landmass.
- Shadowmoon Valley: The Illidari seeks allies to help them eradicate the Demons of Outland where they have the strongest presence in Outland. Tempest Keep has relocated to Shadowmoon Valley to serve as a Forward base for Shattered Sun Offensive.
- Netherstorm: The Manaforges constructed by Kael'Thas lay dormant since he fall...until recently. You must investigate who restarted the Manaforges and most importantly, why.
- Azuremyst Isle/Exodar: The arrival of the Lightforged Draenei is welcome in the aftermath of the fall of Teldrassil, making their land the last safe Alliance stronghold in northwestern Kalimdor. Night Elven refugees from Teldrassil have settled along the southern coast and more arrive every day seeking aid.
- Bloodmyst Isle: The Blood Elves may be long gone but there is still danger as the Kor'kron have established a foothold in the island. The Hand of Argue seeks helps battling the invaders before they can reach The Exodar.
- Eversong Woods/Silvermoon City: Many years have passed but Quel'Thalas continues to rebuild. Rumors of the exiled Void Elves sighted in the Ruins of Silvermoon has the city on edge.
- Ghostlands: Most of the land has been reclaimed from the Scourge thanks to the help of the Forsaken. A new threat has arisen, however: The Wretched and Void Elves they've joined forces with. The Nightborne offer their aid so they can show their new allies what they can do.
- Isle of Quel'Danas: Many years have passed since The Sunwell was purified. Although Quel'Thalas is a part of the Horde, Lorthe'mar Theron has permitted the Alliance passage on the Isle of Quel'Danas at the behest of Vareesa and Alleria. Aventurers can assist
Players can choose weather they want to play the original Outland or the Updated version of it.
...Everything after can stay as-is more or less. LOL this is head canon but I think stuff like this could be done over time with small content updates. Just my 2-cents no one asked for though.