Always thought they create two different kinds of fleets, an carrier attack fleet (with a carrier, but no amphib capability) and an assault fleet, with no carrier (or an escort carrier, perhaps) but several cruisers (with amphib craft enabled). Also, I think it would be cool to add some support ships -- specifically, a tanker, an ammo ship, and a troop ship -- to each fleet that would function in the roles currently performed by the ammo bunkers, fuel depots, and barracks. They could all be modelled on the Liberty Ship, which had tanker and non-tanker versions. Sink one, and it would have the same affect on the fleet as the land bunkers have to airfields.