Remember beggars in Oblivion? They had a different persuasion and rumor voice than the begging lines. I hope it's not like that. :shrug:
Really, you wouldn't need extra voice actors to fix that, just include lines specific to beggars for those subjects, or if Bethesda didn't want to do that, they could just, you know, disable those topics for beggars.
But back on the subject at hand, 70 voice actors probably includes the voices of characters who get unique voices, such as Esbern, and the voices of dragons and other entities that are not among the default playable races but still need to speak, and since we don't know how big those numbers are, it's impossible to predict how many voice actors that leaves for generic race voices, but I'd say that AT LEAST we can expect each race to have a distinct voice for males and females, rather than being like Oblivion where some races shared voices (Nords and Orcs, Khajiit and Argonians, and all elves, namely.) hopefully, we'll also hear more characters with unique voices than Oblivion, though, and hopefully they turn out to be less underused than the Emperor. If you're going to go out of your way to hire Patrick Stewart for your game, you really shouldn't have the character he voices be someone who dies within the first half hour of gameplay.