Roger Sutton over on the Horn Book blog has recently read George Eliot’s Middlemarch (which I confess to reading and disliking intensely).
He makes a point which Scott Westerfeld made to me about using language for children in an as yet to be transcribed interview. Writers need to push the boundaries of their language for children to encourage readers to acquire and adopt a greater vocabulary. Reading isn’t necessarily easy and whilst themes and tones may be considering beyond the pale, language appears to be only occasionally following this.
Pullman does good language as does Neil Gaiman and this is for the best, I think anyhow.