More uninspired raid armor sets.
More cases like the horses mounts in BfA and worg mounts in WoD while the shop has unique models.
More contrived gating (Nazjatar) or RNG gating (Mechagon)
More underwhelming narratives and cutscenes in important raids.
More shitting on Tyrande/night elves
More of the story being a collection of rule of cool moments loosely connected by the veneer of an actual cohesive plotline.
More cases of one step forward, two steps back policies.
More of Blizzard tiptoeing and flipping back and forth on whether Sylvanas is bad or just misunderstood or actually a hero.
Luckily, there are also ways in which BfA sucked for me personally that they can't repeat. Like their treatment of N'Zoth or how underwhelming Nazjatar and Ny'alotha both really were. It'd probably be hard for them to make Shadowlands as meh for me as BfA was.