Below are alterations or clarifications I have made to existing pathfinder feats.
Combat Feats
Critical Focus
Original
You are trained in the art of causing pain.
Prerequisites: Base attack bonus +9.
Benefit: Your critical hit chance is increased by 2%
Improved Critical
Original
Attacks made with your chosen weapon are quite deadly.
Prerequisite: Proficient with weapon, base attack bonus +8.
Benefit: When using the weapon you selected, your critical hit chance is increased by 2%
Special: You can gain Improved Critical multiple times. The effects do not stack. Each time you take the feat, it applies to a new type of weapon.
This effect doesn't stack with a keen weapon but it does stack with critical focus.
Weapon Finesse
Original
You are trained in using your agility in melee combat, as opposed to brute strength.
Benefit: With a light weapon, elven curve blade, rapier, whip, or spiked chain made for a creature of your size category, you may use your Dexterity modifier instead of your Strength modifier on attack rolls. If you carry a shield, its armor check penalty applies to your attack rolls. This agile combat style also provides you with greater damage than you'd expect from strength alone, use half of your dexterity modifier (rounded down) instead your strength modifier (or whichever is higher) for damage rolls.
Special: Natural weapons and touch attacks are considered light weapons. Offhand attacks gain a quarter of your dexterity modifier and two handed light weapons gain your full dexterity modifier.
