Anyway, I want some criticism, comments, questions, and ideas about each. Some have additional expansions which I will also not post today.
Your defensive techniques, though highly advanced, heavily rely on the presence of one weapon.
Prerequisites: Proficiency with one weapon.
Benefit: Choose one one-handed or two-handed weapon you are proficient with. While wielding this weapon you gain a +1 Shield bonus to armor class. When wielding this weapon in each hand you instead gain a +2 Shield bonus to armor class.
Special: While not wielding any of the weapons chosen through this feat you suffer a -1 penalty to armor class as a result of your reliance on a single or a handful of defensive weapons.
You may choose this feat multiple times. It's effects do not stack. Each time it applies to a different weapon.
You can deflect the attacks of others with your weapon.
Prerequisites: Defensive Weapon, Base Attack Bonus +6.
Benefit: You may use your Defense Weapon to parry attacks when taking the full attack action. This is done by forgoing attacks with it. You may forgo some, all, or only one of the iterative attacks you are eligible to when taking a full attack action. You may not forgo attacks granted from feats, spells, and magical weapon qualities with the exception of wielding two weapons (see special).
By forgoing an iterative attack you are granted a Shield bonus of a fifth of its total attack bonus (minimum of +1) until the beginning of your next turn. Do not apply target-specific modifiers such as those granted by Bane or a Favored Enemy -- apply only modifiers that apply to all targets, such as your Strength or Dexterity modifier, the weapon's general enhancement bonus, and feat bonuses such as from Weapon Focus. You may apply temporary but not target-specific bonuses to your attack bonuses for the purpose of determining the Shield bonus you gain from forgoing attacks. If some condition, such as fighting with two weapons, causes you to suffer a penalty to your attack bonus you must include it when calculating the Shield bonus gained from each attack.
When you forgo more than one attack the Shield bonuses you gain from each stack with themselves. That is, by forgoing 2 attacks with an attack bonus of +18/+13/+8 (the 1st and the 2nd) you gain a Shield bonus of +5.
Special: When fighting with two weapons you may forgo the iterative attacks you gain from your off hand weapon (you only gain iterative attacks if you have the Two Weapon Multi-attack feat) just like with your primary weapon. The Shield bonuses you gain from each weapon stacks just like when forgoing multiple attacks with the same weapon.
Example: Marcus the Fighter is wielding a longsword in each hand (longswords are Marcus' Defense Weapon). Having the Oversized Two Weapon Fighting, Two Weapon Combat, and Two Weapon Multi-attack feats and 2 attacks per round, his full attack bonuses look like this: +15/+10 // +15/+10. Marcus decides to forgo his second attack with one of his weapons and both attacks with the other using the Combat Parry feat. This grants him a Shield bonus of +7 to armor class until the beginning of his next turn. Note that this bonus does not stack with Marcus' normal +2 Shield bonus for wielding his Defense Weapon in each hand.
Full Shield Defense
Where others would use their great two handed weapons to attack opponents with great power, you maneuver your shield to block devastating attacks.
Prerequisites: Shield Specialization (Heavy or Light), Base Attack Bonus +6.
Benefit: When wearing a light or heavy shield and taking a full attack action you may increase the Shield bonus it grants to armor class by a third your highest attack bonus until your next turn. You cannot bash or otherwise deal damage with your shield, even with the I. Shield Bash feat, and still take advantage of this feat.
You can attempt to unbalance opponents with attacks made with your shield.
Prerequisites: Shield Specialization (Heavy or Light).
Benefit: As a part of a full attack action you can attempt to make a shield slam attack with a shield you wear. This attack is a touch attack made at your highest base attack bonus, though with a -5 penalty. If you hit the target creature with this attack you can attempt a Strength check opposed to the target's Constitution check to unbalance that creature. You gain a +2 bonus on this check if you have dealt damage to the creature this round and an additional +2 bonus if you are wielding a Heavy shield. Creatures gain a +4 bonus on this check for every size category they are larger than medium and a -4 penalty for every size category they are smaller than medium.
If the check succeeds the target suffers a -2 penalty to armor class until the end of your current turn. For every 5 points your check result is greater than the target's increase this penalty by an additional -1, up to the maximum of -5.
Two Weapon Combat
You can effectively wield a weapon in your off hand.
Prerequisites: Dex 13.
Benefit: When fighting with two weapons you take a -4 penalty on off hand attacks and as a -2 penalty on primary hand attacks. If you wield a light weapon in your off hand you instead take a -2 penalty on both off hand and primary attacks.
This feat also allows you to make as many iterative attacks with your off hand weapon as with your primary weapon when taking the full attack action.
Normal: A character wielding a weapon in her off hand suffers a -10 penalty on attacks with the off hand and a -6 penalty on attacks with the primary hand when attacking with both weapons as a part of a full attack action. Wielding a light weapon in the off hand decreases these penalties by 2 for each hand.
A character wielding a weapon in her off hand can make a single attack with it when taking the full attack action.
Special: If you are a Drow you face a special restriction when you select this feat. If you attack with two different scimitars in a single round you instantly enter a state of utter, excruciating agony that lasts for eternity while you are held in suspended animation (similar to Temporal Stasis). You gain no save against this effect. Only the direct intervention of a deity may release you from this state, but all deities hate you.
Also, the scimitars turn into teddy bears.
Skilful Two Weapon Combat
Your ability to wield two weapons has improved.
Prerequisites: Dex 15, Base Attack Bonus +3, Two Weapon Combat.
Benefit: Decrease your two weapon fighting penalties by 2 for each hand.
Normal: A character fighting with two weapons using the Two Weapon Combat (or Two Weapon Fighting for that matter) feat suffers a -2 penalty on attack rolls with each hand when wielding a light weapon in the off hand or a -4 penalty on attack rolls with each hand when wielding a one-handed weapon in the off hand.
A) Nerfed TWC, added STWC
B) Removed the Rend thing.