I've not bought Civ4 yet, but I will be soon. Being a big Civ3 fan, what I'd like to see fixed is:
(all of these points are related to the single player game)
1. If you have a small war with a country in (say) the year 3600BC, quite often they hate you for the remaining 6000 years of the game! A lot of the time I find that all nations hate me for no reason. If a nation is "gratious" towards me, it's not unusual for them to declare war with no provocation. (when I say "me", I assume it's nothing personal). Anyway, I'd like to see the enemy civs attitudes be a bit more realistic.
2. The worker units on "autopilot" are rubbish! All they do is build roads and mines, tearing up my carefully irrigated land that allows my cities to grow in size. Putting them on manual gets very tedious and repetitive.
3. The Civ AI's war tactics are really stupid too, especially in overseas wars. Imagine you want to re-create the D-day landings and start to occupy an entire enemy continent. I would send over dozens of battleships, 100 tanks and a huge amount of planes for cover (a lot of hardware). However, the computer's attempt at a D-day landing will usually be 8 units maximum. No match for a continent full of enemy ground units.
4. Why can't I build a city in the mountains?
5. Did anyone else find that jet fighters were hopeless at bombing anything?
Well, apart from a few annoying things (I'm sure there's more) I really love Civ3
