The "Constitutional Debate" in Herodotus (Book III.80-82)

Otanes' Speech: Megabyzus' Speech: Darius' Speech: "Theory of Unchecked Sovereignty"
Is " who will rule?" the fundamental question? or is it "How should we construct the system so that good rulers do well and are rewarded, while bad rulers are reigned in and disciplined?"

or is it "How should we set up society so that good rulers benefit and improve the ruled and do not self-seek?"