Attorneys have to win arbitrations for their clients. Arbitrators, generally speaking, are only concerned with the result or the esoteric process of arriving at the decision. Attorneys may recommend a certain course of action, but arbitrators only receive and consider the evidence and then pass judgment. Since counsel are judged by their record of success and not really by whether they had a good or bad hand, winning a case must be the main concern for their own self-preservation and career advancement. Arbitrators, on the other hand, don't feel the same economic and professional pressure, and enjoy the olympic spirit in which participating is more important than winning.
Different parties have different expectations as to an arbitrator's required qualifications.
I served as chairman on a panel which unanimously rejected the broker's interpretation. The point was made that, if the arbitrators had been brokers, they would have reached a different conclusion. All three were past presidents of the SMA, experienced arbitrators and, moreover, individuals who had the ability to understand, digest and apply the arguments and principles presented to them during the proceedings. You don't need a specialist panel to hear a particular case, since the burden of persuasion is upon counsel representing the parties. They have to convince you as to the correctness or probability of their position, for which they retain experts.