There are key technologies that upgrade the navigation:
- Sailing allows Builders to embark (ancient era)
- Celestial Navigation allows Traders to embark (classical era)
- Great Lighthouse gives +1 Movement to all naval units, including embarked units (classical era)
- Shipbuilding allows all land units to embark (classical era).
- Mathematics give +1 Movement for all naval units, excluding embarked units (classical era)
- Cartography allows Ocean movement (renaissance era)
- Square Rigging give +1 Movement for embarked units (renaissance era)
- Steam Power give +2 Movement for embarked units (industrial era)
- Combustion give +1 Movement for embarked units (modern era).
By the modern era, land units should have 6 Movement, 7 with the Great Lighthouse, but you are stuck at 2 Movement half of the game until Square Rigging.
Maybe something should be done to make some units better at navigation. I have two ideas. The first one is using the Escort Mobility promotion:
Formation units all inherit escort's Movement spreed. The Melee Naval unit tree could inherit this ability, ending with 3 clear naval units:
- Melee Naval: Faster but doesn't have Ranged Attack. Made for Exploration or Escort.
- Ranged Naval: Powerful but slower. Made for Destroying Cities or Units.
- Raider Naval: Invisible but frail. Made for Destroying Naval units or Raiding.
The second idea is to make some unit more suitable to cross ocean: Cavalry are less praticable to move around since it is easier to shove human than horse on a raft. For example, when the melee units have their Commando ability have +1 Movement, it kind of made Amphibious mediocre in comparison. Amphibious could inherit like +1 or +2 Movement when embarked. It would make a clear distinction between Cavalry fast at home continent but slow to use abroad, and the opposite for Melee.
Ocean itself should something else than being a giant blue plain of peaceful emptiness. It is just boring: there is no risk/reward from trying to cross it early since you are prevented to cross an arbitrary ocean tiles until Cartography. I like the "Lost at Sea" mechanic from humankind that allows you 1 turn being in the Ocean before being deleted, or naval units to loose HP per turn instead. That "Lost at Sea" mechanic would suit better for Civilization.
Maybe the Ocean should be more dynamic with a current system that could increase or decrease the Movement cost, or a wind system that could make navigation with Square Rigging faster if the wind align where we want to go (becoming obsolete with Steam Power). Maybe Ocean should be more strategic with Fog to hide yourself but reduce your vision (impossible to predict the current / wind), some weather event or something else.
In short:
- New ideas should be explored:
- Allows Naval Melee to escort land units fast if in formation.
- Maybe that will make the 3 naval units type more distinct.
- Create a difference between Cavalry and non-Cavalry units, so the former can cross faster.
- Maybe update the Amphibious promotion from Melee units to grant +1 or +2 Movement when embarked.
- Make Ocean more interesting:
- Allowing the ability to cross early the Ocean tiles at a risk, like the Lost at Sea mechanic from Humankind.
- Add a Current system, that would increase or decrease the Movement cost of a tile.
- Add a Wind system, that could decrease the Movement cost of a tile if the Wind is favorable.
- Make Ocean more interesting with some features, weather or events.
