Well then we get to Oblivion, EVERY response is from a voice actor/actress.
I completely understand the ABSOLUTELY DAUNTING task of finding enough voice actors and actresses to create or more diverse feel, but I think it's imperative. Not to mention how difficult it would ALSO be to have MANY things recorded; different responses to things, depending on disposition, when in combat, and of course, quest related topics, among a wide variety of miscellaneous game topics.
I'm sure there's other topics like this, but perhaps not addressing? Dunno.