Personally, I would find even a very simple AI, as long as it plays under the exact same rules as the player, potentially more interesting than the admittedly cool stuff civ4 has. I just felt a bit cheated once I got better at the game and read up on it, e.g. there is not a single difficulty level where players and AI are simply equal, and people reported the AI having fishy knowledge of things going on at the other end of the map.
To me, even an AI that plays along very simple patterns can be fun while I am still figuring out those patterns; but if it's having cheaty knowledge, then even the fun I had becomes a bit unfun in hindsight once I saw through that.
Just my 2 cents and all that, of course, not trying to tell you how to make your game ^^ Just encouraging you that even super simple AI might be fun. Of course multiplayer is the best, but even then, having derpy AI in the middle to use against other humans = always fun, as long as the AI is consistent and doesn't cheat, IMHO.
To me, even an AI that plays along very simple patterns can be fun while I am still figuring out those patterns; but if it's having cheaty knowledge, then even the fun I had becomes a bit unfun in hindsight once I saw through that.
Just my 2 cents and all that, of course, not trying to tell you how to make your game ^^ Just encouraging you that even super simple AI might be fun. Of course multiplayer is the best, but even then, having derpy AI in the middle to use against other humans = always fun, as long as the AI is consistent and doesn't cheat, IMHO.