By contrasting these stories, the Torah seems to be articulating norms about legitimate dissent and authority's reasonable response to it. Korach's rebellion is illegitimate and meets with disaster. The daughters of Zelophehad make a reasonable petition and meet with success - reasonable challenges to reasonable authorities ought to be accepted. Abraham's challenge to God is appropriate and is met with reasoned discussion. Moses' petition to Pharaoh for an Israelite festival is met with tyrannical oppression - illegitimate authority will respond inappropriately and may be challenged more aggressively (to wit, the Plagues).
While the Torah's stories model a healthy give-and-take between authority figures and their dissenters, Jewish history is rife with instances in which individuals are punished for challenging the established beliefs and/or customs of their times. Elisha ben Abuyah, a first century Talmudic scholar, was branded a heretic because of his secular (Hellenistic) studies, and Baruch Spinoza, regarded today as a brilliant ethicist, was excommunicated in the 17th century for his blasphemous ideas. In neither of these examples do the dissenters' actions mirror the extremity of Korach's challenge, yet they are punished for violating the established laws, rules and expectations of the Jewish authorities of the times. We have not always lived up to the Torah's model of engaging with the reasonable dissenters among us.
I'd pick several nits on the descriptions and details, but go with the big themes.
I'd appreciate some serious learning on "The metaphor of kingship in a democratic age"--the metaphor (especially prevalent in Jewish liturgy, as well as in Hasidic tales) doesn't work very well for me (I'm more into immanence than transcendence in my theology), and the Korach story has its place in that discussion.