d20 Combat Redesigned 2 - Playtested

[Moniker]

In summation:
 

Armor Class will be as Damage Reduction. Each armor type will reduce damage by weapon type (Slash/Crush/Pierce). Meaning, a person with a dagger likely cannot harm someone in half plate unless they attempt a Called Shot to Bypass Armor(at a penalty of the DR versus the weapon type).

A new Defense will work as how armor class used to. This is calculated as a pure bonus, based off of the total Reflex save, shield bonus and any miscellaneous modifiers. A defense roll is made everytime a player is hit with a weapon in order to determine whether they've been hit. Since Defense bonuses per class are lower, the Defense roll is treated much like any other skill in the game (flat bonuses plus a d20). In a sense, it gives greater dynamism since Defense will be notibly lower.

AC equals total Reflex, pluS shield and miscellaneous modifiers (for instance, steel armor in my game gives a +1 to AC since it is lighter than iron). This roll is made everytime someone has the potential to get hit with a weapon.

Hit Points now work as thus:
1st level classes that use a D4 gets 2+Con bonus per level. No rolling required
1st level classes that use a D6 gets 3+Con bonus per level. No rolling required
1st level classes that use a D8 gets 4+Con bonus per level. No rolling required
1st level classes that use a D10 gets 5+Con bonus per level. No rolling required
1st level classes that use a D12 gets 6+Con bonus per level. No rolling required

Weapon Adjustments: None
Criticals remain the same, and are still the most direct way to kill someone.

Damage Resistance by Armor Type:
http://deismaar.pbwiki.com/Armor+Resistances+by+Weapon+Type

Sneak Attack:
Sneak attacks no longer do multiple dice of damage. Everytime an extra D6 is given for a sneak attack, it inflicts an additional 3 damage instead of an extra d6 (under normal rules 5d6 - it now will be 1d6+12 damage).

Spell Adjustments:
Spells that have incrimental dice (like a 5th level fireball is normally 5d6) adjust as well. Basically, they do a D6+3 damage multiplied per level [5th level fireball does 1d6+12 damage)

Basically, all dice boil down to these new conventions (in regards to multiple dice for spells - weapons are under exclusion in order to bring parity between high level casters and weapon users:
d4 is represented by a flat 2
d6 is represented by a flat 3
d8 is represented by a flat  4
d10 is represented by a flat 5
d12 is represented by a flat  6

In essence, it will cut HP in half, make combat more dangerous yet more dynamic and cut down the amount of real time it takes to resolve combat. Our gaming group are heavy roleplayers, but we have a tendency for combat to be long (1.5 hours to resolve 8 rounds of difficultm multiple combatants involved in a sortie). Soon, it becomes a battle of attrition and ends up losing a lot of the immersion as multiple dice are rolled. Since our game is extremely low magic (no one has ever witnessed a fireball or even a magic missile in the seven years we've been playing this campaign), this intensely speeds up combat and adds a new level of danger without nerfing character classes.

We playtested it this weekend in several different mock combat scenarios (including one with a fighter and a wizard-type character [Diviner]. We ran into a few hangups over how cover should work, but otherwise the players were very receptive. We worked through how critical hits should work, eliminated the need for a natural 20 always successfully hitting and introduced critical fumbles on a natural 1 (in order to compliment the Critical Hits range on weapons).

A few things:
Dodge now gives a flat +1 bonus to AC, no matter who the opponent is
Combat Expertise becomes a very viable method for protection for Fighters
Rogues had a tendancy to have better AC at the sacrifice of being able to absorb damage (DR). Fighters were hit more often, but their armor absorbed a lot more than rogues in DR.
Cover provides +4 to the AC when fighting under cover

I am having a few issues with resolving fundamental rules (like cover and concealment) in regard to DR and/or AC.

[Seraph]

All in all I'd say I rather like this system.  I've been using a parry-option system for my game, though just last night I came across the 3.0 rules for the defense roll and I rather like that idea, and yours.  I might consider using one or the other.  I like how it feels a bit more realistic, keeping PCs from reaching incredulously superhuman hit points, but also having to do more to hurt them at all.  Having it be a roll instead of a fixed score brings in the shifting feel of a battle, and the room for human error.  A trick of the eye leads the character to dodge left--into the path of his enemy's blade.  Of course specifics like that would still have to be roleplayed, but it at least keeps things from being static.

Oh, the one minor thing I would suggest (which perhaps you intended to include but did not state) is that if Con increases after first level so as to give a larger bonus, then characters should gain the extra hp(s) that increase provides.  It would still be only for the one level, so it would not make a drastic impact on total hp, but I think it's only fair for the bonus to affect everything to which it is relevant.

[Moniker]

Indeed, Constitution bonus applies for first and every level thereafter in this ruleset. I might have mistated it.

[Pellanor]

Hit Points now work as thus:
Constitution modifier only works with first level HP

That line has lead to a fair amount of confusion. You might want to rewrite it.

[Seraph]

You know what?  I LOVE your system.  I love how it gives a more natural feel without being ultra gritty.  
Looking at the page where you discuss hit points, I rather like the simple ways in which characters can get little bits of healing in the midst of combat without resorting to magic.

A couple things though: Serious Wounds (such as broken bones and deep cuts) heal in one day?  That's pretty damn quick.  But it is a game, so I suppose having the characters function at lower power for the game equivalent of two months wouldn't be very fun.
Also, slashing not doing much against platemail.  In general, I would very much agree with this.  The problem comes up when axes are involved.  Battle axes were one of the few weapons capable of penetrating plate armor in the middle ages/renaissance.  Perhaps this is not worth taking into account in game terms, as it is only axes, but it's something to think about.  Perhaps axes should fall into a different damage category?  That might be the simplest way to work things (If you even care about the axes, which you may not.)

EDIT:  Oh, also, I'm not sure why steel armor should add to the armor class for being light.  Light though it may be, padded or leather armors do not add to armor class but are unquestionable lighter still.