Earlier today I was doing a couple of 7th Legion quests in Tiraguard Sound and noticed that my fresh level 50 MM Hunter was taking a serious beatdown on every mob. I continued on anyway as it was a four part quest chain. Part one and two were brutally punishing killing my pet (and nearly me) on every pull. The mobs were more like Elites.
When I got to part three the mobs were normally powered and I was taking them down in a reasonable amount of time while taking a reasonable amount of damage. All the mobs in each part of the quest chain were the same, non elite, mobs. Some were very overpowered some were normal.
Part four was killing a rare silver mob. After the first attempt and untimely death, I decided to wait for 3 other players to help me take this guy down. They appeared to be well geared and it still took us at least 3 minutes or more to get the kill that before the pre-patch would have taken 30 seconds or less.
I get that wasting resources on balancing old content right now would be counterproductive to getting Shadowlands out but, to me, this signifies a serious underlying problem with the level squish and subsequent power balance of players and mobs which will absolutely cause problems even after SL drops.