I began playing civ strategy games since Microprose's Civilization on the Super Nintendo. (god, that makes me sound old at age 23)
Compared to Civilization II on the PC with CTP II that I have now, the AI seemed a little better in Civilization II. In CTP II, without modifications, the AI appeared to be illogical and flawed.
But there are modifications that I did, and one of those was increasing the time allowed for AI to make decisions in its turn. Find the post on it in Creation section.
Now, after making this and other modifications, I believe I have seen a little improvement - nothing dramatic though.