Has the options to see which dungeon that contains the most upgrades been removed, or can i just simple not find it? i mean in legion, you could see like for an example that blackrook hold contained 4 better items, than the ones currently equipped… Do i have to scroll down the upgrade finder and count myself? 
We might add some more upgrade finder search types.
For now, you can use the Bonus Roll search and filter it to only dungeons (since you can bonus roll M+ dungeons now). We might add a way to do a similar search on non-M+ dungeons, though an M2 dungeon bonus roll search should give you a pretty similar list to a mythic dungeon search, it is only 5 ilvls different.
Okay, thanks alot and have a nice day 