So what shall I do? Go buy the book and read it, or spend what time I have for leisure listening to all these nattering nabobs of negativism?
One thing that Byatt said was, I think, whistfully telling. In complaining that CoH doesn't give enough development or information about the characters--so that she doesn't care about them--she said that she was absolutely sure that Tolkien's head held that information, that he had fully imagined all the characters. And that she recognizes the wonderful aspect of his thoughts about language change, and that she really quite regretted that this fullness was not brought out in the text, despite the constant changing of sword names etc.
It's as if she recognizes that Tolkien had a genius and regrets that it doesn't come through in this text. So, is she more generous than most of the nay-sayers? I'm not sure. This could simply be that very British way of being backhandedly snarky. Yes, that's it, I think. Now I shall go snooping through her novels trying to decide what nasty sort of character actually speaks with her voice.
Oh, yes, and of course she claims her credentials about northern myths. I recognise the type.