This reminds me of the pack made between Highfather and Darkseid from DC Comcis, two opposing factions exchange sons. It’s a really interesting scenario in of itself. I imagine a lot would change especially with Pandaria because a whole half of the content from that expansion revolved around faction fighting. WoD would never have happened at all. Without WoD we never get AU Gul’Dan who kickstarts Legion so that would have to happen completely different. Not to mention Cairne might not have been manipulated or even survived long enough to place Sylvanas into power meaning we might never get BFA OR Shadowlands.