they definitely needed more voices for the generic population. you just keep hearing the same ones over and over - doesn't help that they all start talking as sooon as you are anywhere near them.
also, doesn't help that you somewhat distinctive voices. actors i hear on a lot of characters:
- claudia christensen (ivanova from b5) once i recognized her, i heard her everywhere. she is the smith in whirerun, the jarl in rifen and at least half the generic nord women you meet.
- pretty much all the nord guys are one voice too, including ralof and hakon. it's paul ganus (i keep thinking he sounds like bratac from sg1, but it's not the same guy, just similar voice). if you join the stormcloaks, you will hear his voice (and the guy who voices ulfric) almost exclusively during that quest line.
- all the male dark elves i have heard are keith szarabajk (looked up the spelling

. the vampire hunter guy who tormented angel during season 3. you hear him a lot in other games and in animation too.
- lani minella is all the female dark elves and several named npcs too. she has a really recognizable voice too. i remember her from a lot of fantasy games, but the only one i can think of atm is dungeon siege.
- heard linda carter (wonder woman) again, she used to be all the nords and orcs in oblivion, now she's just a few people though. i think she was azura too.
- heard the oblivion guard guy again, wes johnston. not only sheogorath, but several other places too.
if they really had 70 actors, they definitely underused them.