I'm pretty sure other people has commented on this in other threads - but I did a quick search and I couldn't find a thread dedicated to it. The naval AI is in dire need of improvement. I completed my first full game last night and after I secured my own continent, I built a few naval vessels and pretty much ruled the seas for the remainder of the game. Even though the other civs declared war on me at various times they never even remotely tried anything aggressive with their navys, never tried to invade, and hardly even defended their coasts. Monty had by far the largest civ and military (I was third), yet I just sailed up and down his coasts, pummeling coastal cities. the stupid russian AI kept on embarking land unit after land unit within range of my destroyer off shore. They only built ironclads and they never tried to attack my ships as a group. Also, I experienced several instances of an enemy ship in range of a hostile city state just sitting there until is was sunk by bombardment! I guess the playtesters only used pangea maps! This really makes the later stages of a game uninteresting (unless you are on pangea). Oh well, hopefully there is some work in progress on these issues.