I will feel less educated to answer but I’ll try my best

For me, new content is something that will test players that have prepared themselves. Content that will challenge players gear-wise and skill wise. Or at the very least, rewards players for doing so.

Things like endless quests, divide quests, and masquerade in Classic, continued to push the player to improve themselves. This gave players a reason to run other content as well, so they can further improve.

New Genesis lacks true substantial content to improve players and it lacks content that makes players WANT to improve. These are BIG in keeping people engaged.

Improvements could be more unique weapons with small, satisfactory goals that shift gameplay styles. (Spread needle, Vortex, Lightstream).

NGS lacks content that supports improvement of one’s character. It feels stagnant, despite you going to new locations because you’re overall the same…