I think +3 to a skill is okay mechanically, but it certainly isn't sexy. Its just a bonus you slap on, and unlike feats like weapon focus, doesn't really lead into anything. So how's this to spice up the feat a bit.
Skill Focus:
You choose one skill and gain +3 to the skill. In addition, once per day per 4 ranks in the skill (minimum 1) you can choose to take 10 in the skill when you normally wouldn't be able to.
Skill Focus:
You choose one skill and gain +3 to the skill. In addition, once per day per 4 ranks in the skill (minimum 1) you can choose to take 10 in the skill when you normally wouldn't be able to.