While the QDRO fiduciary's lawyer appears particularly dispicable, union plans in particular are really terrible at complying with the law, out of either incompetence or misplaced knee-jerk support of the union member. However, I doubt that there is anything you can do formally because you did such a good job of lawyering that you avoided an outcome that was a breach of fiduicary duty. Had you been unsuccessful at persuasion and forced to pursue the claims procedure, or other path, to court, you could have made the fiduciary suffer fees and costs, as you pointed out. With respect to the lawyer, since he or she was dealing with another lawyer (you), I doubt that any sanction is available under the applicable code of legal ethics. The lawyer was zealously advocating for the (misguided) client. And that lawyer can say to you, with impunity, whatever the lawyer chooses. Your success is your worst enemy with respect to your desire for discipline. And the DOL doesn't care becuase the DOL doesn't understand QDROs (but I am glad you could put the DOL's marginal materials to good use), but more importantly the DOL is too busy dealing with achieved breach of fiduciary duty to trifle with a failed attempt. So you are left with informal measures, such as public shaming, which are inadequate if only for lack of a forum that has a relevant audience. I am not aware of a website that has a ratings or a bashing platform that would reach a QDRO audience. I note that you did not name names here. And what would you say? XYZ Lawyer is either an ignoramus or a knave, but can ultimately be defeated by a persistent super competent professional?
Or maybe you could punch him/her out in a back alley, which is what I felt like doing a lot before I switched career paths and left litigation, much to my integrity, inner peace, and possible longevity (as yet undetermined). Too much skullduggery is tolerated, or at leat not punished, under this "zealous advocacy" BS.
My dig at the DOL was not properly formulated in context or properly focused, but I am going to leave it anyway, because one should never pass up an opportunity to point out the DOL's shortcomings with respect to QDROs.