Where is it stated that she's more powerful than Deathwing, especially Cata DW? And by whom? I don't remember that bit at all, only that Mannoroth thought her about as powerful as KJ or Archimonde... two beings that are far more plot-relevant than her and who both were mid-tier bosses in passing.
As for Sargeras respecting her, qué? He had eyes only for Azeroth, she was a pawn like any other, to be used in his invasion.
Azshara was on the level of Kil'Jaeden before the sundering, seeing as how the dragons did not do all too well during War of the Ancients, it can be surmised that Kil'jaeden is stronger than the Aspects. Now I know Deathwing is the strongest of the Aspects, especially after his treachery with the Dragon Soul and then being empowered by N'zoth, but Azshara was also empowered by N'zoth without losing her sanity to boot, so it is not within the unlikely realm to estimate Azshara has surpassed Deathwing's power. Is it a lore stated fact? No, but the clues are there.
Well yeah, everyone and everything is a pawn to Sargeras, but that doesn't mean he doesn't respect his highest lieutenants (Kil'jaeden/Archimonde/Azshara) more than lower servants such as Gul'dan, or else he wouldn't trust them to lead his crusade.
Holy lore assumptions Batman. Is Garrosh also stronger than Deathwing, considering he explicitly was not corrupted by the Heart of Y'shaarj, a stronger OG than N'zoth? Or maybe is it that Azshara was rotten and did not require corruption to serve N'zoth, whereas Neltharion was a fairly benevolent Aspect before he was twisted beyond recognition. Your clues mean little as these are completely different scenarios, and your claim rests on little but hype for her.
And what crusade has Azshara led? Archimonde led the Legion forces during the War of the Ancients in Sargeras's stead. Azshara's role was literally that of Gul'dan in Legion: convenient portal opener.
Neltharion benevolent? Hardly when he already conspired for power long before N'zoth dug his shady tentacles into his brain. I don't even think Garrosh was stronger than Lei Shen to be honest. Garrosh in his mortal guise was matched evenly with Cairne Bloodhoof. He had Y'shaarj's heart; what is that but a pulsing organ with remnant power of an Old God who's been dead how long? It gave him a substantial power up that allowed him to make sport of Thrall (which is no small feat sure) but it hardly made him as strong as Lei Shen or anyone comparable.
If Azshara was as strong as Kil'jaeden and Archimonde 10 thousand years ago, and it can be implied she has grown stronger since being empowered, much like Deathwing, is it not a sweeping assumption that Deathwing is indeed stronger than Azshara if Kil'jaeden is proven more powerful than any of the aspects then, and Azshara was on equal footing with him?
Azshara led no crusades, it was an example that if her power was equal to Kil'jaeden and Archimonde BACK THEN as Mannoroth concluded, then she would be viewed as equal to them in Sargegras' eyes. The only difference is she didn't become subservient to Sargeras whereas they did.
8.2 will flop just as hard as the rest of BFA
Non nobis Domine, non nobis, sed nomini tuo da gloriam
Class changes make me miss mop
Allies Race Wishlist: ALLIANCE: Tuskarr and Vrykul HORDE: Gnoll and Mok'Nathal
New Class Wishlist: Blademaster, Tinker, Necromancer, Bard