I liked nearly everything about the videos but at the same time they reinforced my worries about the AI, especially the combat AI.
AI navies still look hopeless. On Deity, the player is at war with both the Danes and the Celts, and they achieve nothing in the turns we saw. AI units are being slaughtered and they still can't build any decent naval invasion or even a limited threat. And that's even without the player really defending the cities.
Looks like standard maps or even pangea will be the way to go for a challenge, but even then I doubt combat AI has been improved that much. Firaxis should understand a single player game is only as good as its AI, it's a major point in the game. You can have the best features in the world, they're useless if your opponent isn't challenging...
Civ 4 stack fights weren't perfect, but at least in Civ 4 the opponents knew how to make a decent city attack and a decent naval invasion (especially with BetterAI mod). I know it's a lot harder now without stacks, but it's essential for the game to be enjoyable.
