Could not possibly agree more with the dungeon thing. A mix of old Dynamis (huge map, hordes of enemies, several different paths to take, long duration), new Dynamis (ability to sneak through certain locations), Limbus/Salvage (different objectives for each dungeon, different and more complex mechanics to progress), Einherjar (tiered system, although with better accessibility for final dungeon, if there is such a thing) and Voidwatch (tough NMs).

And if I could also mention something it should not have:
- Staggering mobs, because fuck staggering
- Detrimental effects that you have to work through, like disabling subjobs, or magic, or gear, etc. This is just a lazy way of artificially increasing difficulty (or the time wasting factor), without actually increasing it. It's what ruined Salvage for me. We have jobs and gear leveled so we can use them. Make stuff genuinely difficult, don't restrict our ability to play the game.