Svest, you can win before the AI gets artillery? Man, I suck then . What map and size were you playing? My guess is just like that Civ 4, larger map sizes are harder. Maybe you should move up to huge?
Anyways Civ 4 was dumb too. The AI just died to mass air or 2-move units. There was even code that said made Rifles defensive only unit so they just sat in their cities while your cannons owned them. So....why don't people knock Civ 4 for this? .
I have been doing random map settings/random leader lately. Keeps things a bit more interesting IMO. I think the game I was talking about was continents, probably standard size. When I saw I got Ghandi I decided to go for the 3 city cultural win for the Bollywood achievement. That's the only reason the game made it that long.
I've also done a large earth map, but I got Alexander so that might not be very fair. All of Europe, Asia, and Africa fell to 4 companion cavalry and 2 catapults (I didn't bother finishing the game by going over to the Americas).
Actually lately I've been playing on immortal instead of deity. I found slogging through their billion units to just be more annoying than challenging. So instead I play immortal and hamstring myself in some way hoping to make it more challenging. For example, in my current game I got an archipelago map and I thought it might be interesting to try to win without ever building a single land unit (military - settlers and workers were fine). I figured if I couldn't conquer any cities it might up the challenge a bit. Sadly I was disappointed to find the AI is more than willing to give you all their cities for peace still (which I thought was something that was supposed to be fixed).
Maybe I'll give a huge map on deity a try. If you say it will be a bigger challenge its worth a shot.
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For the second part, the reason people didn't notice the stupidity as much in CivIV was because the SOD mechanics allowed for stupidity. It was harder to use a little thought to gain a HUGE advantage when fighting SOD vs SOD. Yeah, you had to make sure you struck first, but that was about it. If their SOD had 30 units and you only had 10 you were in trouble. In CiV if they have 30 units and you have 10 you are golden.
The added complexity of 1UPT vs SOD really brought the AI's shortcomings into the spotlight.