Aight boys, let’s discuss this. Does Sylvanas even need a redemption arc?
Let’s start with the 4th war. Sylvanas, who has constantly seen the undead and the horde exist at the mercy of the Alliance claimed to fear an azerite-fueled arms race, which the Alliance would win and use the weapons to finish off the Horde. During the BFA opening we see the azerite machines the Alliance has managed to create in such a short time, so her fear wasn’t unjustified.
The “alleged” genocide is really a far-fetched idea. Sylvanas at the time wasn’t going after numbers. She really knew in a full-on battle, the Alliance would win. This is why she relied on subversion, and make sure to draw the elven armies away from Darnassus and Teldrassil to ensure they could conquer the places. I’m not sure we can call it a genocide if first you make sure the majority of elves aren’t there. Sure, many died, but eh… it’s war.
Due to a war being inevitable, with both factions working on massive azerite weaponry, Sylvanas is being at best accelerationist, and at worst someone who deliberately breaks a broken system to expose how broken it is.
But what if it is a genocide. Now, at this stage Sylvanas fully knows what happens and she knows the entire structure of life and death. Sylvanas is also an accelerationist. She knows when people die, they aren’t ever dead. They just go to the infinite life, which is Death. Life is but a flicker, an irrelevant string of non-choices that you don’t get to have, before you’re sent to be an eternal servant in death. And you can’t even choose who you serve.
For Sylvanas it really doesn’t matter because a) nobody has any choice ever. This will be used for the Arthas redemption arc, mark my words. We will be told he isn’t responsible because The Helm of Domination controlled him. But how’s that different from Fate controlling us? Did Arthas even have the choice to not put the Helm on? Or was he always fated to do so?
We are but pawns in a greater game. We are small worker bees used for our energy by grand beings who have no interest in us as beings, but as tools. As fuel. And we consider them good? Why? How can someone who erases choice from your entire existence be good? How can someone who determines your fate before your birth be good?
Sylvanas is rather villainous, but all she did is… burn down a corrupted tree, accelerated an inevitable war and accelerated inevitable deaths. Think of everyone we have killed in pursuit of “good”. We broke the machine of death in this pursuit, and opened the floodgates to everything that’s happened. We, the player character, aren’t one to judge Sylvanas. Her sins can’t compare to ours. And all she wants is to give us the freedom to not live out these rotten fates.