SRD said: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. [...]
Flynn said:I agree with the consensus. The feat says "You gain a +1 bonus on all attack rolls you make using the selected weapon." The first stage of a grapple is an attack roll. This is where the feat gives you the bonus.
Hypersmurf said:Right, but it's Weapon Focus (Grapple) that gives you +1 on your attack roll to initiate a grapple, not Weapon Focus (Unarmed Strike).
The rules allow you to make all kinds of suboptimal choices. You can be a shuriken specialist if you want, for example. You'd probably be better off as a longbow specialist, but the choice is there for you to make.Zephiel7 said:One question though: What is the point of building a grappler? You can't initiate a grapple against roughly one third - one half of the creatures in the monster manual (due to size constraints).

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.