While they never were going to get to wipe out the forsaken, player character race and all, the idea the forsaken were written with, that they alliance hates their guts doesn’t apply anymore, largely from blizzards attempts to whitewash the alliance.
The Forsaken’s storyline wasn’t complex, it’s kinda in their name, they got cursed with undeath so humanity and the light forsook them. So their story was a mix of bitter conflict and hatred between both sides as well as trying to get revenge on the man who did this to them.
Then Wrathgate happened and completely destroyed any semblance of the Forsaken story going forward. They became a force that only existed to antagonize the other playable races, and got almost completely left out of the final conflict with the Lich King outside of one dungeon with Sylvanas. Come cataclysm and the writers seemed to have decided they we’re to be the “Neo-Scourge” with the first drafts literally involving mind-controlling the newly raised until they realized that was a complete and utter destruction of the few remaining forsaken themes.
The writers never really liked the Forsaken as they were given them do to them being from a weird place in development history. WC3 and WoW entered development pretty close to each other tmk, and the Forsaken were created with the idea it was gonna be like WC2, with them literally being named Scourge in the game files. When it turned out the Horde opposed the Scourge, and was a lot less evil, they still wanted to have undead, so the WC3 team during the frozen throne campaign made the Forsaken, who were still the most villainous faction but had some factors that made them sympathetic and would allow the rest of the Horde to tolerate them (The Apothecary early on had moments of actually acting like doctors, using their knowledge of alchemy and surgery to help the horde out and not just poison and lobotomize people). After Wrath the WC3 writers began to slowly step back and in general it was a bit of a mess. Cataclysm did have some decent moments, like Jekyll being impressed by the Dwarfs spirits still trying to defend their home after their deaths and sent a false report saying the hold was unsalvagable, but as time went on those moments (already somewhat infrequent) got less and less frequent.
Allianceside meanwhile they were having Varian effectively purge stormwind of it’s “flaws”, they neutered the House of Nobles, made the issues regarding food a result of the Defias and began to downplay the hatred of the undead, though that wouldn’t come to fruition until Anduin shows up as High King. So while they were making the Forsaken get worse, they were making the Alliance get better.
Finally this leads to BfA, which is just the previous issues exasperated tenfold. It looked like we were going to get closer to symapthetic undead again with Zelling, but he then died solely to show how evil Sylvanas is, meanwhile Calia began to exist which made the last reason the Forsaken name exist, they were Forsaken by the light, pointless as well. It’s incredibly annoying that one of my favorite races became a cartoon caricature of itself, but thats modern wow for yah.