It's the games systems of calculation for damage. Almost every game uses a percentage based system. So if someone hits you with 50 damage and you have 50 damage reduction your hp goes down by 25. Dragons Dogma doesn't do this, and instead opts for a game where the points are literal. So if someone hits you with 50 damage and you have 50 damage reduction no damage is taken at all except on crits. In my opinion that is a horrible system. For my end game it turned most major enemies into a huge grind because they have insanely high damage reduction.
I'm done with my first play through now. Overall that Bitterblack DLC was hell at first, but over the last few weeks I've been doing regular Daimon runs to finish out the last quest I needed to complete (Trappings of Evil). My characters are ridiculously geared now, outside of Bitterblack nothing really touches me. I never really had much trouble with the regular questing in Dragon's Dogma, so I get the impression either you rushed the main story, or I took a really long time getting to it (opting for sidequests/monster hunting), or a little of both. I understand where you were coming from in the calculations. I've had similar thoughts sometimes in Fallout as it pertains to Perks that mitigate damage differently with either Damage Reduction or Damage Resistance. On the other hand, I think if you're taking your time in DD to explore, do the sidequests, and occasionally go out and hunt for monster parts for upgrading gear then you're probably not going to have any issues with difficulty. It seems like the game focuses a lot on Enhancing gear to make sure you're up to par in fights, especially since unenhanced gear is often on par or can be far below Enhanced stuff. I did enjoy maxing out armor sets though, and hunting for the materials to make it happen. There's just something cool about dragon hunting, climbing on the back of a wyvern, and gashing it's weak spot with your dagger repeatedly till it came crashing to the ground...and then looting the corpse for Enhancement materials.
I'm going to keep playing the game in the future, but I bought a couple more games in the Winter Steam sale and plan on checking those out. Been wanting to try the old X3 space games for some time and see how they stack up as a space sim. I'm also kind of interested in this game I've been seeing called My Summer Car, haven't bought it yet. It's getting very good reviews, and part of me wants to check it out...just not sure how long I'll end up getting into it and what the end game is. In any case, the trailers crack me up:
<iframe width="560" height="315" src="https://www.youtube.com/embed/ZzPdPYtqBt0" frameborder="0" allowfullscreen></iframe>
<iframe width="560" height="315" src="https://www.youtube.com/embed/XBitEX-8IcM" frameborder="0" allowfullscreen></iframe>