1) all npc's in oblivion have voice. in morrowind only few story npcs have.
n what ways did Skyrim and Oblivion change from Morrowind to reduce the 'filler dialog' problem you're talking about?
2) in oblivion each minor npc has 1-4 topics you can ask, that are UNIQUE.
in morrowind each minor npc has 10-30 topics, that you have to ask until they get grayd.
Kingdom of amalur got jealous and copied morrowind dialog flaws.
3) oblivion has some memorable npcs e.g the lady that loved the rats (oh my poor babies).
i believe that rpgs cant capture that feeling, only permadeath games can make you worry.
when you really should be worrying about the danger of it all.