I would love to see a recon element in naval combat, with carriers giving a massive bonus as well as some torpedo attack (assuming it's still seperate from fire). I would love to see at least two classes of carrier, one for early seaplane tenders and conversions and one for early fleet carriers. I'd love to see meaningful submarines. But not as much as I'd like to see a well balanced game that's fun to play.
The former (the recon bit) sounds like it should be easily doable (if it isn't already in game in some form?). I mean if you have the same kind of "recon" factor for land combat, just extrapolate that out for naval combat, then give carriers the right stats to reflect their performance during this period: high recon, high defense, and medium-low damage. Then they would play a more "support" role in naval combat (in the same way planes do for land combat).