I’ve always felt that many of the weapons in 3.5/Pathfinder are a little too interchangeable. What’s the real difference between a battleaxe and a warhammer? One pound, two gold, and whether they deal bludgeoning or slashing damage. So unless you’re up against a creature with DR/slashing or DR/bludgeoning, you won’t even be able to tell the difference. In order to combat this, I wanted to try experimenting with some weapon-specific combat feats that give you options to fight differently with different kinds of weapons. I’ve decided to start with the rapier. Enjoy.
Fencer  (Combat)
              Your experience in the  art of fencing has made you a master of slipping past your opponents’ defenses.
              Prerequisite: Weapon  Focus (rapier).
              Benefit: Whenever  you make a melee attack with a rapier, you may take a -2 penalty to your attack  roll in order to make a special combat maneuver check. If you succeed, the  target is denied any dodge or shield bonus to AC for that attack. 
Fencer’s  Foil (Combat)
              You have mastered the  art of defending with your weapon as well as attacking, and you deflect all but  the most determined attacks with your blade.
              Prerequisite: Fencer,  Weapon Focus (rapier), base attack +6.
              Benefit: Whenever  you make a full attack action while wielding a rapier in one hand and holding  nothing in your other hand, you may choose to sacrifice one or more of your  attacks. If you do, you gain a +4 shield bonus to AC until the beginning of the  next round, and for each additional attack sacrificed beyond the first, this  bonus increases by +2. You can sacrifice a maximum number of attacks in this  way equal to 1 less than the total number of attacks you would make (so a  character with a base attack bonus of +6 could sacrifice only 1 attack, while a  character with a base attack bonus of +11 could sacrifice 2 attacks, and so  on).
Fencer’s  Strike (Combat)
              You are adept at  waiting for the moment when your foe creates an opening, and then seizing it.
              Prerequisite: Combat  Reflexes, Fencer, Fencer’s Foil, Weapon Focus (rapier), base attack +11.
              Benefit: As a  full-round action, you can enter a defensive stance and ready yourself for  attack. If you do, then until the beginning of your next turn, any time a  creature makes a melee attack against you, it provokes an attack of  opportunity, allowing you to strike it first. If you hit, in addition to  dealing damage, the target suffers a -4 penalty on its attack roll for that  attack. 
              You can’t  make more attacks in this way each round than you would be able to make with a  full attack action, even if you are able to make more attacks of opportunity  than that in one round. Further, these attacks suffer a cumulative -5 penalty  for each such attack already made since the beginning of your last turn. Other  attacks of opportunity (such as those made against a creature leaving a square  you threaten) do not count towards these penalties and do not suffer such  penalties.
Improved  Fencer (Combat)
              Prerequisite: Fencer,  Weapon Focus (rapier).
              Benefit: Whenever  you use the Fencer feat, if the attempt is successful, in addition to denying  the target any dodge or shield bonus to AC, the target also adds only half his  Dexterity bonus to AC. This does not count as being denied his Dexterity bonus  for the purposes of sneak attack and similar abilities.
Master  Fencer (Combat)
              Prerequisite: Fencer,  Improved Fencer, Weapon Focus (rapier).
              Benefit: Whenever  you use the Fencer feat, if the attempt is successful, in addition to the  normal effects, you also deal an additional point of bleed damage to the  target. This bleed damage stacks with itself, so multiple hits will increase  the amount of bleed damage the target suffers.