Interesting ideas...
Personally, I like the idea of the Warforged's alien mind being more analytical, so a +2 Int feels good (it's also quirky, since they have automatic spell failure chance).
Here's how I'd do a Pathfinder Warforged:
WARFORGED
+2 Constitution, +2 Intelligence, -2 Charisma: Warforged are hardy and have an anlytical method of thinking, however this method of thinking, coupled with the fact that they never experienced growth and learning as a child into an adult, creates a detached sense of individuality.
Medium: Warforged are medium creatures and have no bonuses or penalties from size.
Normal Speed: Warforged have a base speed of 30 feet.
Living Construct: A warforged has the humanoid (living construct) type. They are primarily humanoid, but their creation from non-living stone and wood instills them with a number of construct qualities, granting them the following bonuses:
- A warforged does not need to breathe, eat or sleep. As such, a warforged is immune to sleep effects, or effects that cause fatigue or exhaustion, as well as those that cause nausea or sickened conditions. A warforged still requires 8 hours of rest to prepare spells.
- Since a warforged has no blood, they are immune to bleed, poison and disease.
- A warforged's physiology does not allow healing naturally, and since they are only partially made of once living wood, they are only partially affected by normal curative magic (reduced by 50%). This same physiology also means they automatically stabilize when below 0 hitpoints, and do not risk further damage when performing strenuous activity while staggered at 0 hitpoints.
- Due to the wood, stone and metals used to create it's body, a warforged is always treated as wearing metal, stone and wood armor for purposes of spells that affect such materials. Also, a warforged is treated as a ferrous creature for purposes of spells and abilities such as rusting grasp or the touch of a rust monster's antennae. However, this also means they are treated as constructs for purposes of spells such as mending or make whole.
- A warforged can be repaired with the Knowledge (engineering) skill. This is similar to the long-term care check from the Heal skill (DC 15), repairing 2 hitpoints from 8 hours of repair, or 4 hitpoints for a full day of extended repairing.
In addition, repairing severe damage can be done with a Knowledge (engineering) check, exactly as the treat deadly wound Heal check (DC 20), granting 1 hitpoints per level of the warforged, and if exceeding the DC by 5, adding the bonus from Intelligence. This must be done within 24 hours of the damage, and only once per day. They require the use of Artisan's Tools to perform.
Composite Plating: The plating used to build a warforged provides a +2 armor bonus to AC, however due to being somewhat bulky, also causes a 10% spell failure chance. This is treated as light armor for purposes of class abilities that can ignore spell failure chance. This plating can be enchanted as a normal suit of armor, although the warforged needs to be present for the entire process.
The plating takes up the armor or robe slot. Armor can be "fitted" to be worn around and over the plating; such armor is treated as "non-humanoid" for purposes of cost and weight. Only the highest armor bonus is applied (they do not stack).
Fitted armor or other magical equipment, such as robes, can be normally used overtop the plating, however any enhancements on the plating is suppressed.
Natural Attack: A warforged has a natural attack in the form of a slam that deals 1d4 points of damage.
Languages: Common. A warforged with a high intelligence may choose one additional language based on the region or people from where he was created.
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So overall, I think it normalizes the Warforged a bit, bringing it more in line with the philosophies of Pathfinder.
I took away the energy drain protection (no idea why it had that but not immunity to ability score damage), and Fortification (for obvious reasons).
I also took away the construct type, since the Warforged seems to have more in common with being humanoid than being a construct.
It made for a shorter list of additive things, than a longer list of removed things while still needing to mention the additive things.
It also means they are affected by spells like Hold Person.
If you leave out the repair line of spells, their problem with healing is more in line with balancing their immunities. There's still the mending and make whole spells for somewhat limited magical (but full, and arcane) healing, and the Knowledge (engineering) skill for longterm and "deadly wound" repair.
Fighters being a common "soldier" choice for Warforged having Knowledge (engineering) is suddenly incredibly fitting.
The plating working with armor allows for a more seamless fit into standard games without needing components and a whole slough of warforged exception stuff.
The increased cost and non-automatic fit for found magic armor gives a decent penalty for automatic starting armor.
The lack of Weapon Familiarity is offset by automatic natural attack.
Since this Warforged will have, on average, a +1 Int bonus, I felt that giving them the option of an extra language (appropriate to where they were "born") was fitting.
I think this version of the race will work okay alongside the other races. They will feel the healing issue more keenly, but the adding of skill check to repair, and keeping some of the really good immunities (bleed, poison and sleep/fatigue effects) make it a balanced thing I feel.
I think it still captures the whole "unstoppable army" feel that warforged are supposed to have (automatic armor and attack, no need to sleep, etc), but keeps things within reason for a normal Pathfinder PC race.