The three quills on the broadside are universals. You can make a fairly decent PD ship... actually you can fit almost anything on it, it's extremely flexible. But while the PD is arguably lacking, the ship has no uncovered flank if you kit it accordingly, and the Barracuda Drones and 180 omni shield shore up the rest.
Also, since when doesn't two arguses basically stop any and all missiles from hitting your engines? : p
I have new missiles planned, but a few of them require some coding acrobatics I can't currently handle on my own. I might add one as a placeholder, though.