The problem with Sylvanas’s character, as well as one of her strongest points, is just how incredibly divisive she is. She has both strong detractors, who would throw a fit if she doesn’t die a horrible death, and followers who would throw a fit if she does. This makes writing an ending for her rather difficult.
How do you think could this issue be handled? I personally think it could be done by making the overall ending the same, but with several short in-game cinematics that depend on player choices. Let’s say it goes like this: in an attempt to wrest more power for herself, Sylvanas is enslaved by whatever death god she was trying to usurp (Mueh’zala, for example). So we fight her in a raid, but she’s not herself, and in fact trying to help us destroy her so she could break free. Once we bring her to low health, one of four cinematics plays:
- Horde Loyalist: Having been defeated, Sylvanas lies dying, looking at her champion and thanking you for ending her misery. She has a short, but powerful monologue about how she dies free, and how she respects you for your strength and ruthlessness. Before drawing her last breath, she tells the player about Mueh’zala’s weaknesses, and once that is done, you bring her corpse to Nathanos in a quest so he could bury her as a hero.
- Horde Rebel: As the player approaches Sylvanas’s dying form, she makes a spiteful speech about how the Horde has always been nothing, and how easy it was for her to manipulate it. The player grabs for his weapon, and Sylvanas makes a last, desperate move to make you suffer, but you are faster. Before you make the final blow and decapitate her, one of the Horde characters (maybe Zekhan) says: “You are nothing.” After the fight, you bring her head home and mount it on the spires of Orgrimmar, and Thrall then inspects her body to discover Mueh’zala’s weaknesses.
- Anduin’s follower: The dying Sylvanas looks down in shame, contemplating her life choices and how she now despises herself for being so weak. You offer her your hand, but Sylvanas angrily rejects it, saying that she would rather die free than be a servant to anyone. She then cuts her own throat to end her suffering. After the fight, you use the Light to call a fragment of Sylvanas’s spirit to interrogate her on Mueh’zala’s weaknesses.
- Tyrande’s follower: The dying Sylvanas desperately tries to crawl away from the battlefield, but you grab her before she can do so. You use some sort of Void-empowered sword Tyrande has given you, and realising what is now at stake, she begs for mercy, crying, apologising and trying to justify her actions as you slowly approach her. As she does so, she accidentally tells you of Mueh’zala’s weaknesses. Finally, you open a portal to the Void, which slowly sucks Sylvanas away as she screams in terror, to suffer for all eternity.