Is it possible to apply the weapon focus feat line to unarmed strikes?
That is to say, any or all of the following:
- Weapon Focus
- Weapon Specialization
- Greater Weapon Focus
- Greater Weapon Specialization
Well, if you read the feats, they all explicitly say that you can! Each contains the following line:
So your specific question is easy. A more general question is if that line is necessary -- and I'd say it isn't. The rules consistently treat unarmed strike as just another type of weapon:
So any feats that can apply to a weapon should be applicable to unarmed strike.
You can take Weapon Focus et al. in Natural Weapons
So the admittedly convoluted status of the Unarmed Strike is unimportant: even if you do call it a natural weapon, it’s still eligible for Weapon Focus.
The Unarmed Strike is generally treated as a natural weapon for the purposes of spell effects and feats (if you are a Monk, you also get to treat it like a manufactured weapon for those purposes), but it generally follows the rules of a manufactured weapon (e.g. it gets iteratives, cannot be combined with other manufactured weapons the way natural weapons usually can).
Thus, to answer starwed’s pondering, no, Weapon Focus need not specify unarmed strikes specifically as an option.