So warrior types are not harder to hit, just harder to take down (they have more HP) and agile combatants (Monks, duelists, rogues, etc most of the time they have 150% more AC than heavily armored characters) are more adept to dodge damage but can take less punishment. Makes sense if you put it that way.

I still prefer the DR- based armor system of DAO, gothic or the old tabletop games Exaltado or Vampire: Mascarade.