I loved the morrowind voice, but the dark elves in oblivion were from another place, right? maybe they were born in cyrodiil etc. maybe thats why they werent "raspy" even though prolly it was just bethesda that couldnt be arsed 'bout getting a raspy actor.
my opinion: a mix. 80% morrowind-style with different raspy-ness levels and 20% more oblivion style, maybe more "noble" dark elves have more "refined" voices, more snobby, or w/e