Development continues on the World of Warcraft 9.1.5 update via the PTR. Blizzard decided to answer some questions regarding the dungeon difficulty changes.
Accoridng to a forum post by developer MattVi, a coming PTR build will have some tuning adjustments affecting dungeons. Previously, the team had said that they wanted to scale the dungeon challenge level to approach Shadowlands Mythic+ difficulty, and this is where they feel they are with the coming build.
This doesn't mean that the work is complete, but with testing data and feedback, the dungeon scaling will go ahead. In response to some concerns, however, the response was straightforward, "We’re not looking to drastically change the feel of dungeons or available strategies, but we’re open to changing some things to better match modern player expectations or improve the feel of the dungeon, such as active mitigation mechanics." Some changes, like reducing or disabling the active mitigation requirement, should help flow in the new mechanics.
When you talk about tuning dungeons that are familiar, it's going to raise some questions. The approach was made clear that the modern player is more skilled and, effectively, more prepared, so the tuning should help restore some of the sense of challenge that will also help keep players engaged. Part of this is also found in the automatic Infernal Beacon activation when you pull the boss and engage. This is intended to offer some time-saving strategic choices.
Additional changes include fixing a bug that made Azerite fear and essences functional in those specific dungeons. Overall, Blizzard is taking its time on these dungeon tuning changes, but more will be available once they're all on the PTR and available for wider testing.