If you think I'm scraping the bottom of the barrel for this tech tree, wait until you find out I have next to nothing for the next era
Seafaring - Based on the other tech tree. I figured it would just give either an offensive ship, or maybe a generic Marine (so Sparta has a shot at conquering those one square islands).
Upper Class Troops - This is what I was suggesting about Citizen Hoplites. At the battle of Delium, the Thebans were the first to use an "Elite Hoplite" of 300 specially trained men from the wealthiest class. Additionally, the Argive alliance had a similar group of soldiers (1000 elite soldiers) for the battle of Matinea.
Schools of Thought and Reason - This was in the original tech tree, I don't know its point, I just stuck it in the second age
Modern Hoplite Tactics - At the battle of Delium, Thebes reorganized the right flank to a depth of 25. This is the first recorded example of the very deep wing hoplite formation. At Delium, it didn't succeed as well as at Leuctra (Thebes won by other manuverings, and inspite of this strategy). But it set the stage for later battles. I didn't have any plans for this tech, just make it required for the next age.
Horsemanship - Just a better Cavalry. Maybe some kind of Syracusan Cavalry as well.
Naval Tactics - This tech I was the least sure about. In Sicily at the battle in the Great Harbor, Syracuse used several different tactics to remove any Athenian advantage at sea. First, they reenforced the front of their ships to withstand a head on charge. Secondly, they had Javelin Throwers on each deck shoot at Athenian rowers. These two methods, although only useful in tight situations, desimated the Athenian Navy, and forced them to try and escape on land. In game, this tech should either give you a new ship, or allow you to build improvements for veteran ships (I'll explain more later).
Mercenary Troops - Maybe it could give Persia Mercenary Hoplites. Maybe a few other units (Athens hired Thracian Mercenaries right after the Sicilian expadition). Can't think of anything else right now.
Engineering - More of a suggestion than anything else. I'd suggeest it allows Barricades. Also, allow Longwalls to be built (Argos started to build a Longwall during this time). Make them very expensive, though, so Athens will be glad they don't have to build another one.
That's all I can think of besides some tech for Spartan Armed Helots.
EDIT: About the veteran ship thing:
The Isthman Track is supposed to allow Veteran ships to be built in Corinth. My suggestion is to give the cities of Athen, Corcyra, Syracuse, and any city on Lesbos and Chios similar improvements. At "Naval Tactics", allow you to start getting veteran ships at any city. Just an idea
