Well, there are varying degrees of “redemption” to be had here. And tons of gradients to be considered with even the ones that come from a character’s death.
Just to name a few examples of it in Warcraft’s universe:
Groms death: Redemption that turns former villain into a hero of sorts for a whole group of people previously wronged by his actions.
Elisande/KJ’s death: “Redeeming” death in a way that has the antagonist agreeing with those that ultimately worked to depose him/her, by having a few last humanising moments that grasp at shortsightedness as an excuse of sorts to explain why he/she acted that way.
Illidan’s death: Redeeming sacrifice amidst those that never “fully grasped” the picture that this protagonist (hero or whatever), had already been seeing since the begining. While shouldering the burden by himself, as the rest label him as just some sort of deranged villain.
These three templates all represent different approaches to be had even if we are to consider a scenario that has Sylvanas dying under a more “positive” light.
And all of them are but shots at a “redemption story” for the character, that people may or may not be inclined to accept if/when they take place in the story.
Would these make some people mad? Surely. But bear in mind that there are those that would settle for nothing short of utter humiliation and the chance to physically thrust their torso into the screen and throw a spit onto the characters body (such is the level of obsession reached with her character).
Personally, i think some of the above is a middle ground of sorts that requires certain degree of compromise from both side of the fence.
I mean, this game is also designed to created an appealing experience for those that enjoy the themes that Sylvanas represented. Not only for MHPs and NEFPAs to steamroll it all with either their superiority or prosecution complexes.
Anduin was clearly "puppeteered " by domination magic when he did that thing I would spoil for some, if I said it here. I don’t think Anduin will be killed by anyone, he will live and both the Alliance and Horde will have the task to free him. And again, I enjoy entertaining the idea that Sylvanas will help Anduin get away and she will fight the Jailer. It will be her “Darth Vader throwing the Emperor down the chasm” moment, perhaps Garrosh gets to share that moment of villainy stopped by fallen heroes with Sylvanas and Arthas could be redeemed along the way. It all could be awesome and correct some of the more dire story writing mistakes Blizzard has commited.
I actually used to be rather pessimistic about WoW’s Metaplot, as I couldn’t save most of the people I wanted to save. I never liked what Blizzard did to Kael’thas. I was perfectly fine with him being portrayed as someone who would do anything to save his people and then he was turned into that other character who would betray everyone for power. But, Blizzard did the same to Illidan and then turned that story around just in the nick of time. Before BFA I was concerned that they would turn Jaina Proudmoore into another Garrosh Hellscream, which annoyed me, even as a Horde player I didn’t want to raid Jaina Proudmoore, and then Blizzard turned her story around too, what made me very happy. I have to say I feel the same way about Anduin I don’t want to participate in a raid against him, that said I completely forgot about this, but back in 2009 I actually did particpate in a raid against Stormwind and I received the achievement for killing a young Anduin Wrynn. Anyway, times change I suppose, the wider point I want to make is that when we look back the early expansions are clearly the bigger offenders, when it comes to turning beloved characters into “Loot Pinatas”. They did it to Kael’thas, Illidan, Kael’thas again and Garrosh. I found the story of “Garrosh’s fall” wasn’t told very convincingly. Sylvanas can’t be redeemed and brought back as a hero either, but she and Garrosh still can do that Darth Vader thing and go out in a blaze of glory. Maybe I’m alone with this, but judged by this metric I remember BC, Cataclysm and MoP as the worst expansions. Hence, there is still hope.
What Anduin will experience through his transformation into the jailer’s servant will change him forever. So far, he has always been this youthful character who fought on the side of justice and righteousness. But after the events in Shadowlands, there will be no going back to this Anduin.
Please, if it makes him an Army of the Light zealot, it needs to happen. I don’t care if he lives because of the fanbase, but at least crack his perfect record a bit.