Dude, Sylvanas was always meant to be responsible for the Wrathgate. Her getting away with it was the retcon - Blizzard obviously got cold feet about killing a major faction leader at the battle of undercity and changed things last minute.

Sylvanas and the Wrathgate is Legion and Illidan 2.0 - it’s not really a retcon, it was righting a wrong from bad story telling during the Classic era. 9/10 the people who view Sylvanas as sympathetic didn’t actually play Warcraft 3. She was always meant to be responsible. Hell, just the other day I found some of my old wowhead comments back from early 2009 where I called Blizzard out for chickening out on Wrathgate at the last minute to preserve the status quo. You couldn’t be more wrong about the sequence of events.