I know that there's no accounting for tastes, but this "looks different" thing I just can't understand. For the very original Zoe design that they showed during the Kickstarter I can get that it was looking slightly different (more "round" face, quite different cheekbone structure or something), though still easily recongnizable as her, but the "final" Zoe we have is perfectly identical with Dreamfall's, only with more polygons! Kian has changed more, but I don't see anyone complaining about that.
As for the voice, yes it's really jarring that Ellie can't reprise her role because she is no longer acting (and has moved to Australia), but that's mostly because we don't like our characters changing voice in the middle of a story. From another standpoint though, the new voice actress is on all accounts a very talented and upcoming young actress (and singer!) who is very likely able to give us an amazing performance on par with Sarah Hamilton's April, something that Ellie didn't achieve* in Dreamfall.
*I'm not bashing the girl, she was good, but Hamilton was incredible, and after looking up some information about Charlotte Richie I start to hope that she can be that good.