Sorry for my really late intervention in this but modding Civ3 has been out of my mind since last summer... for personal reasons.... :-(
Anyway the tech-tree covers 3 ages and apart from the Crsuaders and Conquisators there are LOTS of units that can be built through research. For instane gunpowder units, medium and late knights, crossbowmen and militias, siege weapons so except if the file has been modded since I did it, the benefits definitely exist (check the two other ages as well !).