My take on the weapon Focus line of feats!

Weapon Focus [General]
Choose one type of weapon. You can also choose unarmed strike or grapple (or ray, if you are a spellcaster) as your weapon for purposes of this feat.

Prerequisites
Proficiency with selected weapon, base attack bonus +1.

Benefit
You gain a +1 bonus on all attack rolls you make using the selected weapon, as well as a +1 bonus to resist disarm and sunder attempts.

Special
You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon.

A fighter may select Weapon Focus as one of his fighter bonus feats. He must have Weapon Focus with a weapon to gain the Weapon Specialization feat for that weapon.

Weapon Specialization [General]
Choose one type of weapon for which you have already selected the Weapon Focus feat. You can also choose unarmed strike or grapple as your weapon for purposes of this feat. You deal extra damage when using this weapon.

Prerequisites
Proficiency with selected weapon, Weapon Focus with selected weapon, fighter level 4th.

Benefit
You gain a +4 bonus on all damage rolls you make using the selected weapon.

Special
You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon.

A fighter may select Weapon Specialization as one of his fighter bonus feats.


Greater Weapon Focus [General]
Choose one type of weapon for which you have already selected Weapon Focus. You can also choose unarmed strike or grapple as your weapon for purposes of this feat.

Prerequisites
Proficiency with selected weapon, Weapon Focus with selected weapon, fighter level 8th.

Benefit
You gain a +3 bonus on all attack rolls you make using the selected weapon, as well as a +3 bonus to resist disarm and sunder attempts. This bonus stacks with other bonuses on attack rolls, including the one from Weapon Focus (see below).

Special
You can gain Greater Weapon Focus multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon.

A fighter must have Greater Weapon Focus with a given weapon to gain the Greater Weapon Specialization feat for that weapon.

A fighter may select Greater Weapon Focus as one of his fighter bonus feats.

Greater Weapon Specialization [General]
Choose one type of weapon for which you have already selected Weapon Specialization. You can also choose unarmed strike or grapple as your weapon for purposes of this feat.

Prerequisites
Proficiency with selected weapon, Greater Weapon Focus with selected weapon, Weapon Focus with selected weapon, Weapon Specialization with selected weapon, fighter level 12th.

Benefit
You gain a +6 bonus on all damage rolls you make using the selected weapon. This bonus stacks with other bonuses on damage rolls, including the one from Weapon Specialization (see below).

Special
You can gain Greater Weapon Specialization multiple times. Its effects do not stack. Each time you take the feat, it applies to a new type of weapon.

A fighter may select Greater Weapon Specialization as one of his fighter bonus feats.

Weapon Mastery [General]
Choose one type of weapon. You can also choose unarmed strike or grapple (or ray, if you are a spellcaster) as your weapon for purposes of this feat.

Prerequisite
Base attack bonus +8, Proficiency with selected weapon, Weapon Focus with selected weapon, Weapon Specialization with selected weapon,

Benefit
When you select this feat, choose one weapon. When using the selected weapon, you gain a +2 bonus on attack rolls and a +2 bonus on damage rolls. You can wield your weapon against a foe who grapples you with a -5 penalty and without first making a grapple check. In addtion You gain double the damage die to your weapon. ( a long sword now deals 2d8 damage and a greatsword deals 4d6 damage)

Special
You can select this feat more than once. Each time, you can select a new damage type. A fighter can choose Melee Weapon Mastery as one of his fighter bonus feats.

Weapon Supremecy[General]
Choose one type of weapon. You can also choose unarmed strike or grapple (or ray, if you are a spellcaster) as your weapon for purposes of this feat.

Prerequisite
fighter level 18th, Greater Weapon Focus with selected weapon, Greater Weapon Specialization with selected weapon, Proficiency with selected weapon, Weapon Focus with selected weapon, Weapon Mastery with selected weapon, Weapon Specialization with selected weapon,

Benefit
When fighting with the weapon that you choose for this feat, you gain a number of additional advantages. You gain a +4 bonus on all checks made to resist being disarmed. When you take a full attack action, you gain 1 additional attack at your highest base attack bonus. In addition you gain a +1bonus to AC.

Special
You can choose this feat only once, for a single specific kind of weapon. The dedication and focus it requires makes it impossible to gain this feat for more than one weapon.

this looks a bit better than the standard weapon focus feat tree, though weapon focus itself is still a little weak, increasing the attack bonus from +1 to +2 would make it a closer power level to the rest of the chain, in addition, you may want to change it from only allowing fighter levels to also allowing warblades and oa samurai(as both are fairly similar to fighters, and gain fighter bonus feats. Though the warblade does gain an ability that allows it to use at least some fighter only feats, having it listed would make it easier for one to gain these)

Definitely a needed power boost from the old Weapon Focus lines.

I would consider a +2/+4 total from the Weapon Focus lines though...+2 from Weapon Focus, and an additional +2 from Greater Weapon Focus. This makes Weapon Focus a better early pick, and eases entry into the feat chain.

I'd also recommend scaling Weapon Specialization, so it retains its value even into later levels. Perhaps add (2 + 1/4) level level (rounded down, minimum 0) to damage, and raise that to (4 + 1/2) level with Greater Weapon Specialization. It's more damage, sure...but probably not overpowered. I suggest this because +4 damage at levels 1-3 is really potent, but falls off quickly, and this sort of formula (or one like it) will help it stay competitive.

Weapon Supremacy seems fine, but Weapon Mastery is rubbing me the wrong way. I just don't like the mechanics you've picked for it: I already have +Attack and +Damage from Weapon Focus and Weapon Specialization, and this just feels like another number-boosting feat in a chain of number-boosting feats. I'd love to see this cut for a series of tactical feats: Greatsword Mastery, for example, might give me three tricks I can use a Greatsword for. Sure, it increases the amount of homebrewing you'd have to do...but it also would really begin to feel like a reward for following the feat chain. As it is, I'm completely unimpressed with Weapon Mastery, and a weapon-specific (or even weapon group specific) set of tactical options would completely reverse my opinion and make me love the end-game options of this feat change.

Something along these lines...


Weapon Mastery: Greatsword [General] [Fighter]
Prerequisites: Base Attack Bonus +10, Weapon Focus: Greatsword, Weapon Specialization: Greatsword, Greater Weapon Focus: Greatsword, Greater Weapon Specialization: Greatsword, Power Attack, Cleave
Benefit: You gain the following tactical options:
Mighty Swing: When you make a melee attack with a Greatsword, you can choose squares you threaten that are adjacent to each other, and your attacks apply to creatures in those two squares equally. You can use this ability on any attack, even an attack of opportunity or a cleave attempt.
My Sword is My Shield: When fighting defensively with a Greatsword, you gain Damage Reduction X/-, where X is equal to 2 + 1/4 your level (rounded down, minimum 1). When taking the total defense action, you gain Damage Reduction X/-, where X is equal to 5 + 1/2 your level (rounded down, minimum 1).
Cleave in Twain: When Power Attacking with a Greatsword, you gain a +4 bonus to damage for every -2 penalty, instead of the normal +2 damage for a -1 penalty normally associated with 2-handed weapons. Additionally, whenever you threaten a critical hit with a Greatsword, your target takes 2d4 points of Constitution damage.

I think that the feats get good towards the end, but I still feel that the first feats in the tree are too weak. Like + 1. I think that needs to increase, and maybe some other stuff.