Here look at this. http://www.imdb.com/title/tt1073664/fullcredits#cast

The person who played Moira Brown played all these people: Catherine - Mother / Moira Brown / Red / Suzie Mack / Sydney / Anna Holt / Belle Bonny / Brianna / Cherry / Crimson / Fantasia / Lana Danvers / Nova / Rosie / Susan Lancaster / Scribe Yearling

Moira doesn't sound like any of those people, right?

1 actor played 4 races in Oblivion, so 1 actor per race is already an improvement.

well...just remember, I don't doubt the variation of voices. But with 60k lines of dialog, its not a huge step up from oblivion (not even double). So, I expect there to be an improvement in voice quality, some unique voices, like Esbern, but other than that, plain old yucky stuffs.
Also, Cyrodill had a hefty mix of races. I'd imagine Skyrim to be mainly Nord, however.

oblivion had 12. 16 if we're counting DLC. That is not a lot! 70 is way more than double!

Are you talking about the post above you. If you are, I think he meant the dialouge lines in Oblivion aren't even doubled to Skyrim's.

He was talking about how many lines of dialog, not how many voice actors