No, it will not make me think I'm a better diver....Just open to more experiences out here, specifically night dives. The local clubs do a LOT of night dives at La Jolla shores and I'd like to join them. The "night" thing is just a fear of mine. In all honesty, I can see myself doing a TON of dives this summer in the 40'-80' range during the day, I would like the ability to dive some of the wrecks out here, and I am REALLY looking forward to the navigation dive as a confidence booster. I get the whole "c-cards don't make you a better diver" thing.....That's not what I'm after at all.
As Karibelle and Dumpsterdiver say AOW sounds right for you. I took it as soon as I could so that I could dive with an instructor to build confidence and experience while learning new things. I learned to dive and did my first 10 or so dives in the Carribean so I had confidence issues here in the North Atlantic cold murkiness, just like you. Continuing my education when I got home was the best decision I could have made, SSI requires you to have 25 dives prior to AOW but I would have taken it sooner if I could. Again like you, I am not a card collector but I love learning new skills and gaining experience with them.
FWIW night diving is fantastic, the bright lights used for diving will make it easier to spot others in the murky waters and it's just a great adventure.
The deep diving specialty is really just a reiteration of basic safety concepts as they relate to being that far under water (you cannot bolt to the surface, you must solve your problem underwater, what it feels like to be narced, that sort of thing). It sounds like where you are has similar conditions to here so you will probably do the night dives first as deep water in low viz conditions is essentially a night dive even on a bright sunny day.
The best part about gaining confidence at home is when you do travel to blue water conditions you will feel like a pro! Just don't get cocky