This whole thing is vastly out of character for Yrel. Nothing we got in WoD paints her as someone that would go to these extremes. She literally fought side by side with the orc that wanted to commit genocide against her people because he loved war so much. Plus, none of the Lightforged, either before or after Xe'ra explodes, act this way. They don't have any problem working with Orcs from this timeline where they did things even worse than the Draenor AU. The Lights "bad side" has always been portrayed as a willingness to embrace bad causes acting on strong faith, who bend it to their own purposes. The new idea that it promotes this fanaticism is very much at odds with how it has always work and honestly undermines a lot of previous lore, including the fall of Arthas.Honestly, you know who would work better in this case and would allow them to tell the season basic story? Grom. Make him the militant leader of the "Lightforged Orcs." After the last fight in Hellfire he tried to redeem himself, but felt he certainly up short. He can't trust his own judgement. So when he finds out about the lightforging that the Draenai do, he asks to have it done to him. Now he serves the light and is at peace. He decides his people need to know about this better way. He takes it to the Warsong, a clan that feels super guilty about the Iron Horde. They convert. Then other clans start to follow. But them some choose not to and Grom wonders... why? Don't they want redemption? Why would they deny this... unless they want the old ways back. The ways of the Iron Horde... the ways of traitors.So Grom decides to hunt down the traitors. Only the Frostwolves, which other clans consider uncorrupted by the Iron Horde, is left in peace. Eventually other clan refugees pour in, hiding from Groms converted Orcs. The Draenai, along with Yrel, try to help but don't want another war with the orc and many Lightforged believe in Grom, think he has a point. So 30 years later, when the Horde characters return, they find a fanatic Grom that has become twisted in his light bound convictions and a tired, thin stretched Frostwolves clan that is barely holding him back. Because they are the only one left that have not submitted. And Grom knows there are traitors hiding in their ranks.So the scenario is similar, but it's Durotan and Draka that hold off Grom so the Mag'har can escape to Azeroth. Maybe have Yrel show up to team up with Durotan again, echo the Blackhand cinamatic. I think that keeps the same theme but without destroying Yrel and giving Grom another "get out of consequences free" card.
Blizzard continues looking for ways of slipping Gul'dan back into the game xD
Oh sure, Garrosh is apparently a hero in other timelines but Gul'dan is always a jerk. How unfair for the best warlock!
what you say is pretty much logical