One of those supposedly “Titan++” girls was almost overrun by Drust.
Devos almost killed Kyrestia in single combat.
We also were not buffed by anything when we beat Denathrius. We were aided by some powerful underlings of him, but not anything close to a Titan.
They did this once for alliance, Archbishop Benedictus. They turned him into a flunky for Deathwing in a 5-man dungeon leading up to the Dragonsoul raid.
Argus only sped up the regeneration, demons still reform in the Twisting Nether without him.
The Burning Legion as a faction is destroyed. What left are scattered warbands lead by their own warlord.
It’s never left the deft and clever hands of Jaina Dreadlord. Sargeras was her protégé
Only Zovaal was ++, as much as I recall, and likely with the new domination power.
I don’t recall the others were. Anduin almost killed one with just a bit of Arthas’ power. If Blizzard tried to portray these Titans as ++, they failed big time. I can’t see LK Anduin jumping to Agrammar and doing that.
Neither Arthas. H*ck, I can’t see neither of the two jumping and doing that to Deathwing before Deathwing crushes them like ants.
I see them as the Imperial remnant after the New Republic defeated the Empire. They are probably scattered warlords, fight amongst themselves for greater power and would probably never be a threat again until some new leader no one expected emerges to reunite them into a threat once more. I doubt it will be Denathrius, honestly that guy was never really anything special to begin with.
Idk man, I think WoW has seen more than a fair amount of burning legion plots. We had 2 whole expansions solely based on that, + half of WoD.
I think I’d be good never seeing it again.
Same for “Faction War”. It can be a thing. I don’t care. But we’ve now had 2 whole expansions specifically about it now (MoP and BfA), with it maintaining a strong presence in expansions not directly about it as well.
Too much of the same thing isn’t enjoyable to me from a story standpoint.
It’s definitely possible that Denathrius is recovering in the Twisting Nether. It’d be a good place to find cover considering the chaotic nature of demons, the dread lords being his creations, and it’d likely avoid the prying eyes of those in the Shadowlands still searching for him. However, I doubt he’d take up a leadership role, especially with something as chaotic and disorganized as the demon masses likely are without Sargeras to keep order.
For now my assumption is the “Burning Legion” isn’t a thing. However, much like the Scourge are still around and trying to fight for power like Darion mentioned; I imagine the same is with the demons of the Twisting Nether. Inevitably, some story thread will lead us there and we will see the state demons are in, it’ll be interesting.
I’m not saying they need to be the exact same Legion, or hell even that relevant to the overall story except for being a constant threat to Azeroth that keeps us on our toes.
In either case, I stick with the personal belief that an army of demons is significantly more interesting than whatever is happening with the Cosmic War.
The Cosmic War has to twist a bunch of stuff into knots to get to the main thing we all already know is going to happen; Every cosmic force is going to be our enemy and we will stand and defend Azeroth against it. Given how much of a mess Shadowlands ended up being, I do not believe they’ll get to this point in any way that I would consider close to being good.
But an army of demons we already know don’t like us and don’t need some sort of reason that makes me ponder my navel and go “Hm you know maybe?” Yeah. At this point I’d like more of that.
That’s Malchezzar.
“You face not Malchezzar alone, but the legions I command!”
No, Denathrius is not the Legion’s new leader because I doubt he was even affiliated with it, to begin with. He’s not even a demon himself, he’s a venthyr who happens to be the very first one. This wasn’t an intelligent theory the first time it was posted, so it’s not going to be the next thousand times.
The Legion as a faction is more or less in shambles. Sargeras is imprisoned, all of its other leaders are permadead, and they lost the source of their rapid regeneration, so all he would be inheriting is the shattered remnants of an army that was feared across the cosmos until some random mortals put an end to them in their own home. After three expansions of fighting them, I think the story needs to move on.
Dreadlords only cared about the legion as far as it served their own goals. Which failed. But they only have one master. And Denathrius will definitely go take revendreth back and punish his son before he even starts to care about demons. He’s all about death and death being dominant. Why would he even want to lead another cosmic power rather than subjugate it like he wants to subjugate them all
Shhhh! That’s in the next expansion! History of the World Part II - The Return of the Burning Legion. 
We actually don’t know if Zovaal ever “rebuilt” Denathrius. The sword said “zovaal will rebud you” when it absorbed his essence and then dreadlords took the sword, but it never said he actually put Denathrius back together. At the end of the day Denathrius didn’t stop the others from exiling him, even if he did come around later, so i wouldn’t put it past him to tell Mal’ganis and the others that he would do it right after he finished in the Sepulcher (which was his goal the entire time). Also even if Denathrius was reconstructed the twisting nether wouldn’t help him as he doesn’t have a demon soul/a soul consumed by fel. Many dreadlords did (in order for Denathrius to spy on the other cosmic forces) but I think it was supposed to be implied that all the ones we fought in ZM other than Malg were still the way Danathrius made them (ie. Venthyr adjacent)
Long live the Fel! Green goo is cool 
I would say no. While he did create the dreadlords, and a number of them rose to fairly high ranks within the legion, the dreadlords were more second/third tier leadership.
As the dreadlords are effectively double agents, in that they serve the purposes of the legion, they also secretly serve denathrius’s purposes (which are unbeknownst to the legion). Were the dreadlords to break their illusion and reveal their true purpose, the legion as a whole would undoubtedly see they be destroyed.
It’s possible that unlike Sargeras, the Eternal Ones were actually being responsible with their power.
Like they COULD go ultra destructive world ending power mode, but that would cause massive damage to the shadowlands in parts of the shadowlands that really can’t afford to be damaged
Same with Zovaal, once he’s in Zereth Mortis, and especially the Sepulcher, he’s in the core of a very sensitive machine and can’t risk knocking things around too much, so he’s in a doomed situation: either he limits his power and ends up beaten by us, or he brings his full power to bear and damages the Sepulcher
Incidentally Denathrius doesn’t go as far as to destroy his fortress but he does go as far as to unleash massive AoEs across the Boss Arena with little hesitation.
He unleashes attacks twice as powerful as what Argus and Aggramar unleash during their Raid Encounters. Zovaal’s AoEs are smaller yet deal a lot more damage.
Fun Fact: Both Argus and Zovaal have Cosmos-Destroying Attacks(Argus uses a long cast at 40% Health while Zovaal activates his Spell instantly once Azeroth’s World Soul drops below 10% Health) that can One-Shot the entire Cosmos if not stopped in time.
That tells us that World Souls like Azeroth and Argus can end the Cosmos if they sacrifice their existence with Zovaal being capable of sacrificing Azeroth the instant she reaches 10% Health while Argus needs to prep a Spell to sacrifice himself upon reaching 40%.
In otherwords Zovaal could easily have sacrificed anyone of his allies instead of Azeroth but he wanted them alive to witness the end. He wanted an audience that could appreciate what he just did rather than one that would watch their end coming with blank expressions.
Grand Warlock Wilfred Fizzlebang should some how come back then to be the ‘Khadgar’ for the return of Jaraxxus.