The key is to look at their cost and build requirements. 375/70, requires Master Swordsmith and County Militia (hence their low morale and relative sucktitude). They aren't supposed to be the end-all-be-all of mounted units. That role is taken by Lancers (850/85, requires Master Horse Breeder, Master Spearmaker, Master Armourer).

It sounds as though you are arguing from a historical standpoint, which is understandable. But if you want to make them uber-knights, you will need to do more than just buff their stats. They will need higher recruitment/upkeep costs and higher build requirements for balance (maybe change their body type as well). This can all be done by editing the Gendarme line in the unit_prod file for the campaign/mod you are playing, this would be crusaders_unit_prod11.txt for vanilla.