You make some good points. However, it seems to me there are some differences here. First of all, Marc Rich was not operating within our system of justice. He wasn't living here and facing the justice system and confiding in lawyers as part of his defense. He was a fugitive from justice, for goodness sake! There is something wrong, it seems to me, with the concept of using lawyers as a proxy to commit, or hide, criminal activity.
A lawyer (as an advocate) is almost by definition a lobbyist. Judges should not be given the lattitude to nullify attorney-client priviledge by simply declaring certain communications non-priviledged. That's too arbitrary and ripe for abuse.