So we have all of these civs and with few exceptions they play very much alike. One thing I think would help would be something other than military heroes for some civs. For example, everyone wants Phoenicia & Carthage to be trading empire so why not give them a special caravan unit instead of a hero, essentially a great merchant with maybe 1/3rd (or less) of the profit from trade missions and the ability to create a unique building like a bazaar not to unlike the great scientists' academy. Egypt could receive some sort of an engineer with the ability to rush production slightly or maybe build improvements much quicker than normal workers for another example. Lots of possibilities and I think some variety in this special unit could really add some spice to the game and make playing different civs much more interesting.
The Roman Legionary works very well with the March promotion rather than the Commando promotion and it doesn't feel quite as "broken" when used by a human player compared to the AI. First strike immunity (or first strike capability) also works well since many defenders receive first strikes as does Combat II since it opens up additional promotions for newly created units in cities with Barracks.
Allowing all naval units to enter the ocean and increasing the movement required to enter coastal tiles has a good effect on naval warfare, particularly amphibious landings. Currently you seldom have the chance to use your navy to defend against invasions since the attacker will move past you (from their own cities in many cases) and unload in a single turn. It may also be a good idea to allow all naval vessels to enter rival territory since it seems inappropraite for ancient civilizations to even know I'm sailing in their waters, especially when nowhere near their cities, let alone prevent me from doing it. This also makes everybody more vulnerable to amphibious landings despite open borders being harder to get.
The Roman Legionary works very well with the March promotion rather than the Commando promotion and it doesn't feel quite as "broken" when used by a human player compared to the AI. First strike immunity (or first strike capability) also works well since many defenders receive first strikes as does Combat II since it opens up additional promotions for newly created units in cities with Barracks.
Allowing all naval units to enter the ocean and increasing the movement required to enter coastal tiles has a good effect on naval warfare, particularly amphibious landings. Currently you seldom have the chance to use your navy to defend against invasions since the attacker will move past you (from their own cities in many cases) and unload in a single turn. It may also be a good idea to allow all naval vessels to enter rival territory since it seems inappropraite for ancient civilizations to even know I'm sailing in their waters, especially when nowhere near their cities, let alone prevent me from doing it. This also makes everybody more vulnerable to amphibious landings despite open borders being harder to get.