I play dungeons for fun. Latest posts here make me worried about end-game dungeons. I do expect there to be dull dungeons and fun dungeons. *and I hope the Binding Coil to be a fun one*

If a dungeon is speedrunnable - it's a bad dungeon, IMO. "fixing" it by adding more mobs it's a short term fix, making the dungeon less appealing in the long term. I would suggest devs to review the speedrunnable dungeons and make them harder, adding some bonus drops from mobs. Why they don't drop crafting items like the lower level ones do is beyond me. I'm talking about the Amdapor Keep here.

I think Qarn is a good dungeon. The mobs there are clever and dangerous and the bosses are a nice challenge. Besides, you can't bypass most of the mobs, and tactics like killing the stones on platforms are a nice touch from melting mobs just to progress.

TL;DR - Make higher level dungeons harder not by numbers, but using mechanics and add rewards for killing mobs on the way to the bosses.