1) Byzantines were an extension of the Roman Empire. Language and culture aside, Byzantine adopted most thigs from the Romans (because they are Romans as well). The Byzantines later improved their army. They decided on using highly mobile, lightly armoured infantry, supported by heavy cavalry.
We showed that the Byzantines were Greeks, there is no need to go through it again.
And hence the term Byzantine. Which comes from Byzas the founder of Byzantium. Greek King of Megara, next to Corinth and Athens.
The Venetians had a formidiable navy (for a while). Venetians had close ties with Greeks, no? That is why you mnetion Venetians?
No. The Venetians were not Greeks.
You said the Romans were superior than the Greeks of Alexander, and i said the Greek Byzantines were superior to the Romans, and the Venetians were superior to the Byzantines.
In order to see which one out of these ones was the most superior we put them in the relative life-span.
We have done so already, and the conclusion is that considering the relative domination of these people, the Greeks can be considered superior because militaristically they were superior for a longer time-period.