So what was the story of Dragonflight again? Some evil dragons woke up and started shit, then the players stepped into end shit, something something WE CAME TOGETHER AS A FAMILY and all was well?
The dragon backstory was retconned. The lore used to be that the Titans shaped the world and all life on it. The dragons were creations of the Titans. In a Cataclysm book, it was tweaked so that the dragons were once Proto-Drakes, and came into existence after the Titans had reshaped the world. The five characters who eventually become the Aspects bravely fought against a gigantic, cannibalistic proto-Drake named Galakrond. The Titan Keeper Tyr noticed the bravery of these Proto-Drakes and summoned the Titan Pantheon, who blessed the Aspects and their followers, transforming them into the dragons as we know them today, with each Titan giving a Dragonflight specific powers. The Titan Pantheon then departed. Then the dragons lived in peace with the world, taught the Night Elves druidism, and then the War of the Ancients happened where Neltharion went crazy from the old gods' whispers and wiped out most of the Blue Dragonflight, resulting in the surviving Blues going mad and the Blacks becoming hostile to all, resulting in the situation by WoW where you have the three good Dragonflights of red/green/bronze vs the dwindling blues and blacks.
The five Dragon Aspects: Ysera, Alexstraza, Nozdormu, Malygos, and Neltharion.
In the new Dragonflight backstory, we find out that Tyr was not completely benevolent, and had actually been capturing and experimenting upon proto-drakes, so he had probably decided that they would be useful to him before he saw the Aspects fight Galakrond. He was also keeping detailed records on the Aspects, almost as if he viewed them as potential threats. It is also "revealed" that there was a huge dragon civil war (that was never spoken of before). In addition to the five Aspects, it turns out that there were an additional four other dragon leaders (Fyrakk, Iridikron, Raszageth, and Vyranoth), who rejected the Titan's upliftment and remained proto-drakes. After the Titans left, Tyr ordered Alexstraza to have the dragonflights and Titan constructs steal proto-drake eggs and to infuse them with order magic, warping the babies within into dragons. This provoked the civil war in which the proto-drakes who didn't want their young to be warped by the titans, but they lost and were imprisoned.
Three of the four Primal Incarnates: Fyrakk, Iridrikon, and Vyranoth. Not pictured is Raszageth, who dies before this scene. I don't think there is a picture of all four Incarnates together.
Also, Neltharion created yet
another breed of supersoldiers (in addition to his Chromatic and Twilight dragons), called the Dracthyr. His Dracthyr army were fervently loyal to him, but when his mindcontrol gauntlet he used to guarantee no betrayals broke, he immediately put all of his Dracthyr into stasis and then never used them again. It's strange because they idolized him, and Neltharion wasn't afraid of using other armies who had far less loyalty to him. When Black Dragons defected, did Neltharion stop using Black Dragons? No, he didn't. So why stop using the Dracthyr?
Also, the Dragon Isles are retconned in. Apparently Keeper Tyr gifted the Dragons these islands as their home and the dragons are very emotional about the isles, complete with generations of loyal servants and lots of nice support infrastructure, but then they left (why?) and the Dragon Isles were sealed away (why?) and the dragons forgot how to get back home, until the Dragonflight prequel short story in which all dragons just spontaneously remember how to get back home for for no reason. And they never mentioned this homeland during the prior 20 years of WoW and novels. It's also strange that the Waking Shores has supplanted Dragonblight has the hatchery of Dragonkind, Valdrakken has supplanted the Wrymrest Temple as their capital, the Shady Sanctuary has supplanted Hyjal as the Emerald Dragonflight's home, the Temporal Conflux has supplanted the Caverns of Time as the Bronze Dragonflight's home, etc.
The dragon capital city of Valdrakken in the foreground, with Tyrhold in the background.
It's weird that if the Dragon Isles were supposed to be sealed away for tens of thousands of years, that Neltharion somehow returned there to deposit hoards of treasure from the rest of the world. Off of the top of my head, the Forbidden Reach and the Obsidian Citadel have treasure troves which include Naga artifacts (the Naga were created 10,000 years ago at the end of the War of the Ancients), so Neltharion went back to the Dragon Isles sometime after everyone else left. IIRC in the Forbidden Reach hoard, you can find stuff as recent as 20 or 30 years ago.
It also turns out that Neltharion had constructed a huge secret underground fortress and laboratory called Abberus. If Neltharion had Abberus all this time and was able to return to the Dragon Isles, then why did he later make his lair in some cave in Highmountain? Why was he trying to hide eggs in Outland in Beyond the Dark Portal? Why did he retreat to Deepholm? He could have just gone back to Abberus and no one would have known where he was, and if they did then Abberus was far and away his most defensible position, and he had the most resources there with his armies and his laboratories.
Neltharion's underground fortress of Abberus.
Anyway, that's new backstory. As for the actual story that happens in the present:
- In a prerelease short story, all Dragons suddenly become nostalgic for the Dragon Isles, even young dragons like Wrathion who had never lived there, and they all remember how to get back to the Dragon Isles. I don't think why they started feeling this was ever explained.
- Among the mortal races of Azeroth, an anti-Titan movement called the Primalists forms. They don't like Titan tampering and want to preserve what they think is "natural". You fight hundreds of Primalists in Dragonflight but I don't think it is ever explained how this anti-Titan sentiment became popular when the Titans and their agents have been so instrumental in saving the world in present WoW, from the Keepers helping defeat Yogg-Saron in Ulduar, or the Keeper Norushen helping save Pandaria from the Sha, or Keeper Ra helping save Azeroth from N'zoth in BFA. Most mortals' knowledge comes from the dragons and the Dwarf explorers Brann and Magni Bronzebeard, so the infromation on the Titans that the mortal populations are coming from pro-Titan advocates, so the Primalist movement seems inexplicable.
This comic came before the Amirdrassil raid ending cinematic retconned the Azeroth world soul into not being a Titan, when up until that point in the lore, all planetary World Souls were Titanic in nature.
- The game story begins with the Dracthyr starting zone, the Forbidden Reach. Primalists arrive and begin attacking, freeing the Primal Incarnate Raszageth from prison. The Dracthyr wake up from stasis and then get caught up on the tens of thousands of years of history they missed (their master Neltharion going mad and being killed, the death of Malygos, the Sundering, etc). The black dragons Wrathion and Ebyssian arrive, but the Dracthyr inexplicably reject them when they should be the successors to their beloved master Neltharion.
- The four launch levelling questlines are about going around the Dragon Isles, touring and reactivating ancient dragon facilities, meeting the locals, and fighting Primalists. Most of the quests were boring and center around pathetic wimps (Sendrax, that centaur shaman, the Tuskurr men, Kalecgos, that bronze dracthyr in Thaldrazsus, etc) who really had no business being in this franchise.
- In the first raid, Raszageth breaches the Vault of the Incarnates. You kill her but she succeeds in releasing the other incarnates.
Raszageth fight at the end of Vault of the Incarnates, with the other imprisoned incarnates in the background.
- In the Green Dragonflight reputation/renown questline, Malfurion goes to the Shadowlands to trade places with Ysera (who died in Legion). Ysera comes back to Azeroth and appoints her daughter Meritha as the new head of the Green Dragonflight. Night Elf souls are sacrificed to create a new world tree seed which is planted in the Emerald Dream.
- In the patch 10.1 questline, the Primal Incarnate Fyrakk breaches Zaralek Cavern and absorbs Shadowflame magic to become stronger. The ghost of Neltharion gives his children Wrathion, Sabellian, and Ebyssian a guided tour around his underground fortress and laboratory of Abberus, but they reject it. Wrathion and Sabellian choose Ebyssian to become the new Black Dragon Aspect.
- The Primal Incarnate Iridrikon, who was the leader of the Incarnates and set up to be the expansion final boss, quits halfway through the expansion. He goes back in time to right after the proto-drake Galakrond fell, and drains dark magic from Gakalkrond's corpse into some relic. Then he leaves through a portal and says he will be there when the Titans return. Guess we won't be seeing him again for another 5-6 years, not until The Last Titan. Metzen said at Blizzcon that TLT begins when the planet is doomed and we go to Ulduar to call the Titans back for help.
- With their leader Iridikron gone, the two remaining Incarnates, Fyrakk and Vyranoth, begin to splinter. Fyrakk decides he wants to destroy the world with fire, which he intends to do by going to the Emerald Dream and setting the new world tree of Amirdrassil on fire. Vyranoth doesn't want to destroy everything and agrees to a truce with the Dragon Aspects, and the six of them (5 Dragonflights + Vyranoth's forces) attack Fyrakk and his forces in the Emerald Dream. Fyrakk dies, and we get an ending cinematic in which the five Aspects and Vyranoth are empowered by Azeroth world soul. Amirdrassil then manifests in the real world off the coast of the Dragon Isles and will become the new Night Elf capital city. Horde players will be able to visit it too.
- In the epilogue banquet, we find out that Jaina also heard Azeroth's world soul (the only other people we know for sure got visions are Thrall and Anduin). Khadgar might have also heard the voice too. Khadgar teases that Alleria is going to investigate the "Harbinger" soon (Xala'tath, the sixth old god who was imprisoned in the priest artifact dagger and escaped from it in BFA and is the villain of the next expansion). Ysera goes back to the Shadowlands, so presumably Malfurion will be able to come back to Azeroth.
- In the Tyr questline, the Aspects go to Tyrhold and activate a 3D printer to rebuild Tyr. There is a quest where you play as Tyr and he gets a vision where he sees all five original Aspects becoming foes. Four of those events have happened (Neltharion becoming Deathwing, Malygos going mad with grief and being the villain of the Eye of Eternity raid, Nozdormu becoming Murozond, and Ysera being corrupted by the nightmare and killed in Legion). The only thing that hasn't happened yet is Alexstraza becoming hostile, so Alexstraza might turn against Tyr and fight him in a later patch quest.
That's it. There won't be any more raid tiers or zones for Dragonflight. We know that there will be three more patches but we don't know if they will have any quests, so that might be it for the story until TWW releases.