See Robert Archambeau remarks on poetry criticism. I agree, I agree, I agree. But what do you think of William Logan? Doesn't he fulfill, to some extent, Bob's demand for a positively negative criticism (or is he too sarcastic for you)? Some of the recent reviewing in Poetry seems fairly even-handed too.
There ought to be much more of same. Criticism is an art in its own right. The old binary models of the (American) 20th century no longer correspond to reality. Not that big new abstract models should be rushed forward.
Sharp criticism raises the literary stakes : it brings forward the complexity of rival styles and theories. It can be a school for writers.