Melee/Man To Man vs 4th Edition

[Kromm]

Passive Defense was removed primarily because the way to get high PD was to wear the heaviest armor you could afford whilst carrying the largest shield available. This would ding your Dodge score by 1-4, depending on your ST, but raise your Dodge roll by 1-8. Thus, there was a large regime wherein "so much protection that you need to spend FP even to stagger" gave a net +1 to +4 to your odds of ducking a blow. Explanations that this meant dodging just enough that the blow glanced off armor were rejected by most gamers. Doing away with PD solved the problem.

As for why variable, equipment-based PD was replaced by a functionally similar +3 built into the basic defense score: That lets unarmored fighters successfully dodge and parry blows without massive armor and shield, which is more realistic. Unarmored fighters are the ones who dodge and parry, while heavily armored ones tend to rely more on armor stopping blows (a function of DR, not PD).