Are Marines useless?
1) Extra embarked sight and defense is great, however I escort embarked units with warships which also have sight and defense.
2) Amphibious is not bad, but I play with a fairly small, highly trained army and my units usually have this promo by this time.
3) Nothing upgrades to them and they upgrade to nothing.
While I would like to propose a new, complex method of upgrading units based on promotions game-wide, I will settle by suggesting that GWI with the Amphibious promo upgrade to Marines which would upgrade to (Mech Inf) for now.
1) Extra embarked sight and defense is great, however I escort embarked units with warships which also have sight and defense.
2) Amphibious is not bad, but I play with a fairly small, highly trained army and my units usually have this promo by this time.
3) Nothing upgrades to them and they upgrade to nothing.
While I would like to propose a new, complex method of upgrading units based on promotions game-wide, I will settle by suggesting that GWI with the Amphibious promo upgrade to Marines which would upgrade to (Mech Inf) for now.