I know this was kind of covered in the drop a level thread, but how much of a difference do ye think the AI improvement is going to make? Like will it make war dramatically harder, or do ye reckon it will just mean you'll need an extra few Knights/Cavalry/Tanks to capture a city?

One of the flaws of the CivIV AI is that it can hit you hard initially, but if you fend off that first wave, there's nothing left. Why? Poor production. Yes, not the case if you're battling a giant civ that has so many cities that it makes up for poor production in each, but a human can produce more with fewer cities.

I expect that the BtS AI will create production cities and thus be able to keep producing more units in order to carry on a protracted war. If the smarts are there to not send these units at you in dribs and drabs, then it will be harder to beat the AI with force.

Also given whatever nerfing has been done to siege, I expect that the human player is going to feel the pinch. The AI was never good at using siege, so if siege is less powerful, it's to the AI's advantage.