To be fair: The dispute between Tyrande and Anduin was FAR more believeable and relateable than anything that happened with the Horde this expansion. Just imagine for a second the Horde would actually exist and you would have to talk with the leaders and they had to react in a somehow not-completely-mental way....can you imagine this without them outright killing each other on the spot? It would be pure chaos and anarchy.
I think it would have been fine to give the Alliance player the choice to either go with Tyrande and see the whole Nightwarrior thing...OR stay with Anduin and be sent to infiltrate Dazar'Alor with Shaw (the 8.1 War Cmapaign chapter). Two choices need not be totally anathema to each other...they need not be outright enemies. It would just be different causes of action within a faction that are both believeable. Yet, there was no choice...because the entire Nightwarrior thing was rushed in last minute and never really cared about by Blizzard. Just like this horrible excuse of a warfront which all the streamers praised as an "Evolution from Arathi" at first, when now, i am willing to bet, everybody who has played it 5times or more will agree it is actually worse than Arathi and far more boring.
Still, Blizzard - by total accident - created a single actually believeable player-choice-scene in the whole crapfest that is BFA with the argument between Tyrande and Anduin. They just were not competent enough to actually make it a choice.