One of the things I noticed after playing Oblivion was the change in the sound of the Dunmer voices. In Morrowind they had a slightly raspier and older sound to them. One of my favorite lines was "Please, join me." I feel that Bethesda took all of the flavor out or Dark Elves by making them sound nearly identical to humans.
The Shivering Isles came closer to the atmosphere of Morrowind partly due to just the artwork. I'm not sure where I'm going with any this. Nostalgia and Hope?