There's been suggested some good ideas here for increasing the importance of a navy much further. As said by other posters, I also don't think these changes need to be dramatic to be effective indeed. Having a RSP system for naval units could be a possible improvement, though this may not be as easy with the ancient units, but I do like Aussie_Lurker's idea of having a slightly extended promotion tree for naval units. The idea of a possible capturing of an enemy ship and turning it into your own, sounds good (perhaps as a promotion for pre-modern vessels), and maybe one could be allowing the blitz-promotion after some stage, say, Flanking II. Problem a bit is that drydocks come in late indeed to get a bit of experience to start with, but perhaps one can have the harbor allowing you two experience points until the industrial age. That would aready be one promotion 'for free', if you built the harbor. Another suggestion: move a few of the goody huts into coastal water -- simulating a tribe of fishermen. That may encourage people to build some ships, especially if you could get experience from these huts on your vessel, just like the land units can. Allowing the birth of a Great Admiral, which would be exactly the same as a Great General on land, also sounds good.
There's lots of good ideas mentioned above, and I think Firaxis has done a very nice job in setting up the whole new concept, and indeed improved CIV a lot, with modability for instance, but I agree with Aussie_Lurker, that I would prefer to have such a navy out of the box rather then to have to mod it myself -- which I'm frankly not too good at.
Jaca
There's lots of good ideas mentioned above, and I think Firaxis has done a very nice job in setting up the whole new concept, and indeed improved CIV a lot, with modability for instance, but I agree with Aussie_Lurker, that I would prefer to have such a navy out of the box rather then to have to mod it myself -- which I'm frankly not too good at.
Jaca