Not it would not go against lore. Azzinoth was a doomguard commander of the Burning Legion.
Illidan took his glaives. From the Manual of Monsters:
"Over the millennia, Illidan grew more and more adept with the demonic weapons, and likely became more proficient with them than their original owner."
So even for Illidan it was not so easy to use them at first.
These are demon glaives and they still glow with green demon energy. That demon energy turns you is also part of the lore.
"The Skull of Gul'dan was a powerful demonic artifact, his skull was turned into a channeling totem for demonic energy. Illidan became a black demon after consuming the power of the Skull of Gul'dan."
We conclude Warcraft lore: If you consum very much demonic energy you turn into a demon
My quest idea would make perfect sense.
BTW: Metzen did not care about lore during BC, he even made a major mistake with the whole Titan/Draenor story (and admitted it).
quote: "Right… To be totally up-front with you guys, it’s my bad, straight up. The obvious lore contradiction with Sargeras and his encounter with the eredar was clearly documented in the Warcraft III manual." Metzen 2006.
PS: You are very rude.
PPS: I think BT was much easier than ICC 25 heroic.