During the recent campfire chat stream Blizzard announced big changes coming to NMDs and Helltides. There are two separate batches of changes.
The NMD Hotfix
Firstly, with a hotfix coming today, July 21st, Nightmare Dungeon difficulty will be reduced, as the higher end was requiring the very powerful builds that themselves required the affixes that were nerfed in patch 1.1. The specifics weren’t detailed, but the hotfix notes will be released soon, and ahead of the actual changes.
The Monster Density
Patch 1.1.1 is coming in a few weeks (possibly even under 2) and will bring increases to monster density. This increase will be significant and affect all Nightmare Dungeons, as well as most parts of Helltides. There are some Helltide zones and areas that are already very dense, and those will not be changed.
More details on this and the rest of patch 1.1.1 (including Sorc and Barb buffs) are coming in next Friday’s campfire stream.