Listen to this chap, he knows of what he speaks! Consider, Leonidas was an excellent leader, dying in the most honorable way thinkable, and sacrificed his life to give some of his soldiers the opportunity to escape to repel the Persians (successfully) later on (this was left out of "300" for those wanting to base any facts on that movie; remember, it's fictionalized history and therefore not the most accurate of sources, however, still a good movie with great action scenes). At the time, Sparta was considered the "protector of Greece" and therefore its leaders the de facto rulers of Greece, accordingly. Anyways, you've started work on him already so what's the harm in finishing him off?
I agree with this. I'm really turned off by the fact of using a Byzantine leader for any of the Greek eras. First of all, the Byzantines are a seperate civ anyways, and are Roman rather than Greek. Second of all, the Romans never removed all the heads of state from each conquered nation, as is observable in the case of Israel during the Roman rule, where King Herod Antipas was a jewish king of the regions of Galilea and Parea. Typically, the Romans only had "overlords" watching over each part of their empire, as was the case with Pontius Pilatus, the governor of Judea (famous for presiding over the trial of Jesus of Nazareth). This was similar in Greece, where each state such as Thebes, Athens, and Sparta remained seperate but not independent states part of the Roman Empire. In fact, there was a battle at one point where Spartan hoplites were called upon by the Roman army to defeat an invading group of Germanic warriors, a task the Roman legions had been defeated at doing. So, Greek kings still very much existed during the Roman Empire, however, with little political influence beyond their small states. Definitely keep the medieval era head Greek rather than Byzantine.
I'm of a different opinion on this matter. As I already said, the Spartan kings were the de facto rulers of the majority of Greece after taking the title of "protector of Greece" from the Athenians. And in the case of Alexander, he was strictly Macedonian, just like Leonidas was Spartan. He did unite Greece, but again, so did the Spartans (and the Athenians before them) to some effect. It just depends on your definition of uniting a nation in that sense. However, Alexander's empire was referred to as the Macedonian empire and not the Greek empire. So in effect, he was just as great for all of Greece as Pericles and Leonidas.