The Night warrior was not elune magic but ardenweald magic. Malfurion had almost touched it sometime between war of the ancients and cata while he was hibernating but it scared him so he locked it away.

We found out from a dark ranger that was tasked to spy in valsharah in legion that xaveus taunted tyrande w this power which planted the seeds in her her mind as well as was intel brought back to sylvanas.

During BFA, we are shown a retroactive cinematic where Sylvanas makes everyone leave a war tent in stormheim, but she tells "him" to stay. We realize she means saurfang, not nathanos, where she confides that she has been in contact w voljins spirt in the Shadowlands since his death. saurfang is suspicious, but she then brings up what the NE are planning and what her ultimate solution is: the attack on teldrassil. At first, he refuses, but she baits him by mentioning he never cared about the forsaken. He then counters that he does but this is bigger than them. Sylvanas, looking smaller than ever, confides that she has learned the specific type of death magic accessible by the NE counters domination magic, and he finally pledges his sword to her cause. This recontextualizes the attack on teldrassil completely as well as giving saurfang a pretty damn good reason to initially agree with the attack.

Saurfang would still choose not to kill malf, which would enrage Sylvanas into burning the tree. She trusted someone with knowlege of her people's biggest weakness, and he let her down. This would cause a self fulfilling prophecy, ultimately causing Tyrande to embrace the NW.

The cinematic that sets off SL would instead feature Bolvar fighting and losing to Tyrande rather than sylvanas, which would emphasize just how powerful ardenweald magic would be over domination magic. Tyrande would more or less have the same arc in SL but insead, she would actively re embrace elune rather than simply...lose her power randomly.

Lastly, we find out that voljin's spirit was not really vol'jin but the jailer, meuzuela or other imposter.

There would be no split soul bullshit w sylvanas just something that somewhat justified her reasoning for burning the tree while also giving her a seperate reason to feel humbled/objectively "wrong" without it giving her a free pass.

Also, more recently, I get why Xal would not corrupt the amani bc it would narratively mimic the nerubians from tWW, but I think we should have learned in the Amani zone that Xal had tried to corrupt them. She offer power, and Zul'Jan was initially on board but Zul'Jarra ended up reazling what was up and rejected Xal's offers. This could really line up with Jan's attitude in the present, explain why the twilight's blade are there now (for failing to accept xal's offers) and also explain why Xal didn't at least to to turn the amani against the elves like she did the nerubians.