The Marvel comparisons are the most obvious, but what this reminds me of the most is the new Star Wars. Where the writers took turns and each of them was left to follow up on the broad strokes of what the previous guy left behind, all the while hating everything that guy has produced and wanting to do something entirely different with the characters. Except there it was two guys, whereas here it's either two or three, depending on how much of a role Metzen still had in Legion. Metzen was clearly building up for a legitimate faction war expansion of some kind given the cinematic he made and how he framed Sylvanas. Then Afrasiabi wanted to turn Sylvanas into Satan to serve as the Big Bad for Shadowlands and also so he could prove he could do Mists better than Kosak, taking Sylvanas being Warchief from the story but nothing else and making it clear that she was her own antagonist. Then Danuser took over and he really wanted to be with his one true waifu, WC3 Reign of Chaos Sylvanas. Being the only person in the world who cared about that incarnation of the character he was stuck with all the BFA baggage and was left to try and build some tangled drama out of it, only to fail because the twice changed foundation was going in two other completely different directions.
I don't know which version is the worst - the BFA one is obviously the most one-dimensional, but the Shadowlands one is the most pants on head retarded and incomprehensible variant yet, simultaneously having to carry pathos that may have worked in some kind of design doc in an alternate universe where BFA never happened, but since BFA did happen falls apart, yet also put into situations that are impossible to explain in any way but her being immensely stupid. Out of all characters assassinated in this expansion, Kel'thuzad takes the cake by far, in not only being entirely butchered to serve as an announcer character for the Blue Man, but also in that him and Sylvanas being in the same raid yet never referencing each other makes the already ridiculous nature of her working for this obviously, transparently villainous guy even worse.
Usually I can at least follow what the fuck the devs were trying to do even as they fail, but I genuinely have no idea how this managed to pass any kind of writer's room or how you could conceivably make it make sense. Even if BFA didn't exist and so Sylvanas' character interaction would make a bit more sense, you'd still have the Kel'thuzad retcon and the Blue Man being a charisma void to contend with. I suppose you could have her only join the Blue Man once the war effort turns to shit out of desperation but even then you'd fail because there's no way anyone meets this guy and thinks he's on the level. It's like that bit in Cataclysm where the Blue Flight usurper wants Deathwing's help despite Deathwing obviously intending to destroy the world, which no one will survive, except it's not an incidental character in a side story but every single character in the villainous cast except Denathrius.