Should we even be talking about human dignity?

Reading the posts by Brad and Alice made me wonder how Luban's vision of lawyering and its relationship to human dignity responds (or would respond) to criticisms by Ruth Macklin and others that dignity is a "useless concept," and that we should really be talking about autonomy.  I confess to not having read Luban's book yet, so he may already have answered this.  It seems to me that a dignity-centered moral justification of lawyers' work will have significant overlap with an autonomy-centered moral justification, but the overlap will not be total.  I'm not sure, though, how or whether the differences in justifications might translate into differences in the substantive requirements/aspirations of legal ethics.  How, if at all, does the debate over human dignity (not just over its substance, but over its utility as a concept) affect our view of the lawyer's role?