I didn't played english version, But in Polish the dialogs were fantastic.
But as far as I know, it is one of the reasons that CDProjekt is looking for a new Publisher,
because they weren't satisfied how Atari handled the translation.
It wasn't so much the voice actors that I didn't like (well maybe a bit), but more the text and dialogs that I felt were flat.
Did CD Project made only the Polish version internally? In that case, I'd believe you then. Perhaps Atari screwed it up.
I only heard that this is the reason why they have abandoned Atari. Don't know the details.
Either way, they should hire professional english writer to improve the translation, I hope this will be the case for the sequel.
By the way CDProjekt just confirmed that the game is no longer based on aurora.
It's their own engine now, it's name will be revealed along with the official anouncement.
We should expect this to happen soon though.