I actually would love it if some new folks got a chance. Don't get me wrong, I like all of the Bioware regulars so to speak, but hearing the same voices everywhere through out and even across both franchises can get a bit...odd.
Take Jennifer Hale. I love her and her portrayal of Shepard. I find it so iconic, I can't unhear it. When I first heard her as Krem I was like; "What. Why is Commander Shepard speaking with a bad British accent....?" Or hearing Bianca/Voice nr.1 from Saints Row 3 and 4 in every generic asari.
But the worst thing was replaying ME3 after playing DAI and hearing my Inquisitor in Samantha Traynor. I found that character so annoying and I would hate for that feeling to stick with me next time I play DAI. However, Sumalee Montano's performance as Nyreen actually pleasantly surprised me. I never pick her voice for my Inquisitors because she sounds like such a drone to me. But as Nyreen I did enjoy her.
So yeah...Fresh blood would be preferable. At least for new characters. (Though....having Claudia Black voice our female protagonist does seem rather intruiging....)
Also, I doubt we will get cameo's but if we do, I'd actually prefer their respective VA's to return for the part. Not having Mordin's original VA from ME2 was extremely jarring in my opinion.