Greece is built around City-State diplomacy rather than direct conquest or terrain — a steady Influence and Culture engine that scales with how many City-States you befriend rather than how much territory you hold.
"Demokratia" grants Culture for active Endeavors, Sanctions, Diplomatic Projects, and Espionage Actions you started or supported, plus Tourism for every City-State you're Suzerain of — both bonuses increasing further in later Ages. The underlying Influence generation this feeds off of is a simple, unconditional bonus that compounds well with Greece's own Traditions.
The Hoplite is a unique Infantry unit with increased Combat Strength when adjacent to another Hoplite — a genuinely strong defensive formation unit once you have two or more together, though unremarkable alone.
The associated Wonder, the Oracle, must be placed on Rough Terrain and grants Wildcard Attribute Points plus extra Culture when gaining Narrative Event rewards — useful, but widely considered one of the weaker Wonders in the game relative to its build cost.