Wow! i appreciaate you taking the effort to put it for the community. Tamil country is the civilization Cholas represent. Tamils did achieve a great deal of weath by sea bourne trade of pearls, spices and other luxury items of the mideval world. The civ in the game however lacks all late game techs.
Currently Dravidians is the civ with the worst pick rate across all elos across all maps. They are not picked on water either consistently. Thay are not top 5 picks in islands, nomad, salt lake or mediterranean. If you make a civ unpopular for land playstyle, most players will not seek it out to play water either. It should be like vikings and malay. The eco bonus should help both land and water playstyle. This is one of the main reasons I am skeptical of water civs being added to the game. Nobody plays them. Making water civs compatabile with Arabia or Arena is a better design.