Do you miss something on BrainKing.com and would you like to see it here? Post your request into this board! If there is a more specific board for the request, (i.e. game rule changes etc) then it should be posted and discussed on that specific board.
A good rule in the battleship boardgame I have is that each ship has a special attack. Subs can shoot missiles horizontally or vertically until something is het on that row/column. Battleships can hit a 3x3 block of squares, but only once, etc. Rules such as this should be considered for alternative versions i think.