You can be disappointed in presentation, but I think it is a bit dubious to argue that the problem is that the Night Elves don’t win hard enough, because this was content that was intended for both sides. So even though the Night Elves were always going to win, Blizzard wanted it to seem like there was a point for Horde players to have to play through it.
Tyrande brings a perpetual nightfall onto Darkshore and the Night Elves, more or less alone, kick the Horde out of the zone. Nathanos gets a bunch of power-ups, does the villain schtick, and has to flee like a dog.
Keep in mind, again, that this content is supposed to be for both factions. From a Horde player perspective, you are once again forced to be henchman to a stereotypical villain, you are basically powerless (you get to help fight Tyrande and you may as well be fighting a mountain as your attacks are completely ineffectual), and your “win”? Raising two night elf wardens, which is A) evil, B) important because why?, C) actually wrecks the story going forward because it turns the entire warfront into a Night Elf grudge match.
The basic flaw was making warfronts that only one side had a strong stake in. That meant that, emotionally, one side was over invested and the other underinvested. The attempts to make the Horde seem like they had a purpose come off as fake (why am I raising Night Elves and blighting nature, again? I’m a paladin), while trying to make the battle seem close makes the Alliance feel like they aren’t getting enough of a win.
Stromgarde has the same flaw, but to a lesser extent. I challenge you to find one Horde player who was excited to be battling for generic base#63 in a zone that had traditional ties to the Alliance and almost none to the Horde (except Hammerfall, which was oddly left out of the struggle).
Edit: Thus, when Blizzard announced that the Alliance collectively won both warfronts, there was basically a collective roll of the eyes from players. It was pretty obvious from day one that the Alliance was going to win both warfronts. Gee, I wonder which Blizzard is more invested in? Rebuilt Stromgarde or the Horde base put together at the last minute from generic assets? Darkshore as a Night Elf zone, or a blighted wasteland with no story function?
This was the problem with the entire BfA narrative: unclear stakes for one side (literally; Blizzard waited until the end to reveal that Horde players were all chumps who didn’t understand the evil plan they were fighting for) and impossible win conditions for the other (Alliance was never going to get to defeat the Horde). In other words, the exact same mistake that Blizzard made with the last faction war.