Heh, I enjoyed playing it alot on Civ 3 as well. That full earth map of theirs for Civ 3 was fucking nuts. (anywhere from 5 to 30 foods from a given fish square if I remember correctly. Get cities of size 60+)
Actually that was one of my bigger disappointments with Beyond the Sword. Most of what they added Total Realism had either already done or worked on extensively. TR had just about every new unit and building that was added to BtS. Worked hard to improve the spy system, which BtS totally revamped, but I found myself longing for the TR version. The buildings using resources (so that only a certain number of said buildings can be built, according to your resources) was already done in TR, not the same thing as the corporations, but using similar initial concepts.
Those mods will spoil ya. That said though, BtS actually deserved to be called an expansion. It added not only new shit, but entire new game concepts that really add a couple more dimensions to your strategy. Warlords was kind of a disappointment in that regard. However owning Warlords is 100% worthwhile if only to play the TR mod. Can't wait til they put out a BtS version.