Civ III was all kinds of jank when it first came out, even compared to Call to Power II. Even the Complete is pretty garbage comparatively.
I think Schafer has said that before. I don't think he was involved much in either of the expansions.
I toyed with the three units per tile mod and thought that worked as a somewhat decent compromise. Also the one that lets you put different types of units but not the same on a tile.
They did patch up a lot of the problems the AI was having with the one unit per tile thing at release though. By BNW it was nowhere near as bad as it was.