I for one would like to see 4-man dungeons on the difficulty level of Coil that are part of endgame progression with it's difficulty and loot. Put in accessories or upgrade items in those dungeons but with the kicker that they aren't completely spammable like current 4-mans. Either a short dungeon lockout (6 hrs) or entry items that need to be earned to enter them.

And I honestly never found old AK or Pharos all that difficult. They were really straightforward.