If Nolan North is really involved, I think they're probably taking the acting a little more seriously.
I definitely wouldn't replace the original voices, though. They're way too iconic at this point, more than the story, without a doubt. If they can't deliver too well on very emotional scenes, than give up on having emotional scenes at all in the series going forward, that's how important I think the voices are. I wouldn't refuse to play the game if they changed, but I really really hope they don't. At least for V, this is pretty much an IP revival, not just another sequel. This game must sell the idea that everything you loved about DMC is back, they can take more risks with 6 if they want.
Because I believe that a big factor in this game's sales will be nostalgia. People who played DMC way back then and are like "oh, shit, it's back, that's so cool! It looks and sounds like I remember it!", and that hype will also bring more people on board, hearing those cherished memories from old time fans. The last thing Capcom wants for this game's promotion is the people who care the most about the franchise saying "I'm not so sure about that".