My point about "the White Queen" (BBC1) was not that I didn't like modern language versions or employing the writer of "Shameless" to write about the fifteenth century. The reverse, really.
Is the BBC's aim to attract a younger audience? To a ten-part period drama? I doubt it will work. A better approach might be to do it in strikingly modern English. So that it looks like a conscious decision, comparable perhaps to setting Shakespeare's "Coriolanus" in the Yugoslav civil war.
As it is, it just seems as if they are not sure whether it is period or modern. And they forget and get it wrong all the time.