Having not played since 8.0, I can’t speak for 8.1’s storyline, but I think a major problem with BfA’s story, writing and questlines was this:
We spend very little time fighting the opposing faction. The villain on the game’s box art (in my case, Sylvanas) never appears once during the entire leveling process. Fighting her armies and her lieutenants is relegated almost entirely to a series of short, optional, time-gated sidequests. The “main storyline” of the 110-120 zones is spent fighting mundane, cliched, throwaway villains that are vanquished easily in a 5-man dungeon run, and doing random “collect 10 bear asses” quests for the locals.
I remember encountering the Horde in a grand total of two questlines during my main questing experience; both of them were in Stormsong Valley, and both of them were over within an hour.
After the fight for Undercity, I was thirsting for battle. I wanted to blast Sylvanas’ zeppelin out of the sky, land on the front lines of Zandalar and Kul Tiras, and wage war against the enemies who were supposed to be the main villains of the expansion. I wanted to slaughter orcs in pitched battles, infiltrate enemy encampments to gather intelligence, pick off Sylvanas’ lieutenants, and travel through enemy territory and enemy bases on high-stakes missions.
Instead, in Tiragarde Sound, I’m forced to fight random pirates with the typical greedy ambitious disgraced noble at their head. In Drustvar I have to fight another ancient power awakened by dark spirits thirsting for vengeance. And in Stormsong Valley, I fight… yet another ancient power awakened by dark gods thirsting for vengeance. That trope definitely isn’t overused at all.
The marketing portrayed BfA’s story as a story of fantasy warfare. Instead, the fantasy warfare was relegated to time-gated sidequests while the main attraction was the same D&D-esque stories that have been repeated a hundred times over, and executed better by other writers. I think I encountered more Horde during the 1-60 questlines than during the entire 110-120 leveling process.
So in conclusion, the story of BfA was an unfocused narrative mess that didn’t deliver on its own marketing. And once all the interesting questlines had been exhausted, I was way too bored with the class designs, Warfronts (They really should have been PvP, by the way), Island Expeditions, dungeons and raids to try and get back on the proverbial treadmill that is modern WoW’s game design. So I quit. End rant.