Indeed, ArPen is not the right way to go in red sockets at the moment, straight Agi would be far preferable due to low AP and crit rate.
His gear is, for lack of a better term, very poor at the moment so it's hard to advise anything specific. He should chain-run heroics, get tons of emblems and buy at least half a gear set: 2 parts T8.5, 2 parts T7.5, a belt, gloves (current ones are good, not sure if it'd be an upgrade), boots, idol, bracers, cloak, one ring and one trinket. So yeah, lots of possible improvements through emblems alone.
Some enchants are understandably not the best for their respective item slots considering the item quality, but 2 are just not right: Legs and weapon. Legs should have the AP/Crit patch and while Mongoose eventually becomes the better weapon enchant, it is not until later gear levels. So Berserking until then (can wait for the next weapon upgrade).
As for his spec, it is considered the best single-target DPS spec. I don't personally like it very much and I think it should only be used once you know all the fights, are comfortable with them, and probably when you reach the point where you start stacking ArPen (to justify Feral Aggression).
Edit: Bah, I always take too long to post. Hope you can find something useful in there.
Edited, Sep 11th 2009 3:32pm by Selverein