Sylvanas has, over the course of BFA's arc which began with "before the storm," been pointedly, singularly and specifically characterized as the incarnation of current factional hostilities. Genn's hate has been dulled from "all forsaken" to Sylvanas, Anduin's mission statement has gone to a singular note of Sylvanas being the problem, and on the horde side of things, it's all for or against Sylvanas. You can of course RP your character however you want, but the narrative we're being given to work within as far as canon goes is that, yes, Sylvanas alone is ultimately the "problem" perpetuating the faction war.
... And she absolutely must fail in the end, and here's why:
The moment Sylvanas' narrative changed from "what are we but slaves to this torment" to a straight up war on hope, not even just life, but hope, she was doomed.
Warcraft is not a world that allows bleak notes or beats in the story to go unanswered, because despite comparisons being made to its current arc, WoW is not game of thrones or that kind of fantasy. WoW has a rating and an established tone that does allow for some dark moments, but they almost always meet their necessary resolution to stay in its genre's lane as heroic fantasy.
-The Culling of Stratholme: Potentially an objectively evil act, (whether that be in forcing it or enacting it) Dark as all heck, complex and compelling... but also lead to the creation of WoW's archetypical darth vader figure that, yes, was necessarily, ultimately defeated in satisfying fashion. His battlecry was "all life must end," he was the villain, he existed to be defeated and he was. A delayed peak in regards to the valley of darkness that made him, but a necessary, inevitable one.
-The bombing of Theramore: An objectively evil act Perpetrated by a villain who was announced as the final villainous raid boss of MoP, ultimately meeting a villain's end. A dark moment, a necessary, inevitable ending, again compelled by the lane Warcraft must stay in. Again, a peak in the story mandated by the valley that was the bombing itself.
-The Burning of Teldrassil: An objectively evil act, and even though the pressure to not repeat past themes creates many parallels that people will gripe about until its follow-up peak, it is a valley that demands a peak. Unlike Garrosh, Sylvanas has similarities with Arthas in posessing an ephemeral, elemental quality that makes her absolutely evil, only where Arthas declared that all life must end (which, yes, Sylvanas has also mirrored), Sylvanas goes the extra step to extend her warcry to oppose hope.
WoW is not, just not, going to put us in a position where the person crying out against hope in her villainous banter is "right." I don't care if half the playerbase pump their fists for her war cry, her archery, her figure or her awesome voice acting, Sylvanas as an enemy of hope is a capital-V villain and we, as players will be cast against her one way or the other. They are not going to reward loyalty to she who declares war on hope, they are not going to cast your character in canon to go along with that. Again, you can RP however you like, I myself play my characters as vacationing gods from my homebrew D&D world, and while I generally keep that to myself, that's just as canonically wrong as "I'm still With Sylvanas" will turn out to be by the end of this arc. Maaaaybe she'll get Illidan'ed, maybe she'll have some form of twist, but this game, with this rating, in this genre is obligated to have an "Endgame" to follow its "Infinity war." That's the genre we're playing, that's the game we're in.
The moral of the story of this arc is not going to be "go ahead and kill yourself, hope is a lie." That is an obligation that goes above and beyond artistic licence. That's archetypically mandated.
Why make this thread? Honestly, I'm beside msyelf that it seems there are still people thinking that their dollars as players mandate Blizzad to vindicate Sylvanas and, more to the point, maintain a non-optional faction divide. I guess I just really want people to be ready for how this MUST end, to save some heartbreak. Spoiler altert: If you are the type to ragequit the game because I and others like me end up having the option to tank as a bloodelf paladin for human and nightelf playing friends... WoW will make up the difference by eliminating the toxicity of that unreasonable demand that we not have that option. Toxicity costs money. Sylvanas is arguably now an analog for everything wrong and toxic with the playerbase as a result of the faction war. She therefore must be defeated. Maybe that means capital-D death, maybe that means putting on the Lich King's crown and becoming an actual PVEvil entity, maybe that means exile to the shadowlands and becoming the face of the spirit healer forevermore, but it will mean a defeat of some kind, because the battle for Azeroth is likely in part a battle against toxicity: Point out the problems with having us all hate each other, personify those problems, then defeat those personifications.
The villain on the box for BFA is the faction divide. The villain on the box is always defeated. (Except in MoP where there was no villain synonymous with the expansion, but the expansion announcement was immediately followed by "Garrosh is the final boss.")