Let's get one thing straight - while Azshara may have done some unsavory things, as far as Warcraft characters go she is nowhere near Gul'dan, Sylvanas or Archimonde levels of evil. Here are some of Azshara's virtuous qualities:
1. Azshara pursued knowledge. She turned her palace into a massive research facility and had the Highborne study the Well of Eternity instead of engaging in their usual decadence. During her reign the Night Elves made remarkable breakthroughs in the understanding of leylines, the arcane and teleportation technologies.
What did Tyrande do during her reign? That's right, she lived in a treehouse until Sylvanas set it on fire and dedicated the Night Elves to the worship of a sky fairy that didn't answer their pleas for help when it mattered the most.
2. Azshara understood diplomacy. She forged a peace treaty with the Zandalari to stop their incursions into the Night Elven Empire and the peace actually lasted for years.
What did Tyrande's diplomacy accomplish? She couldn't even get her formal allies to help the Night Elves retake their lands.
3. Azshara tolerated other beliefs. While she may not have liked the Wild Gods, she tolerated them and let them live in peace on Mount Hyjal. And she built Temples of Elune even thought she thought the arcane was the greater power.
Tyrande, on the other hand, insulted Velen when he DARED suggest that Elune might be a Naaru even though she herself knows jackshit about Elune. And Velen is actually a lot older, more experienced and most importantly a better leader than her. Malfurion was right. Tyrande really should keep her mouth shut.
4. Azshara was progressive. Her inner circle consisted of both men and women. Even after her subjects were transformed into the Naga with men having a monstrous appearance and being more suited to melee combat, she still had equal representation in her court.
Tyrande, on the other hand, took an egalitarian society and turned it sexist with sharply divided gender roles. What the fuck, Tyrande?
5. But most important of all, Azshara cared for her subjects. Not in a benevolent way, but she saw them more as her toys and she didn't want other people hurting them. When push came to shove, she tried to save her empire with her own hands.
Tyrande doesn't care for anyone other than Malfurion. When Teldrassil was about to be occupied she convenient left the battlefield. Can you imagine Azshara abandoning her subjects and her capital to the enemy? I sure as hell can't.
I look forward to Azshara's redemption story. She should come back as the true queen of the Night Elves and restore them to their former glory. No more Elune worship, no more treehouses, no more hillbilly sexism. The Night Elves will rebuild their empire under Azshara's guidance and become a force to be reckoned with once more.
Bonus round: Azshara was classy and elegant. For all her ornaments and gems, Tyrande still looks gaudy rather than queenly.