Your build is looking really good honestly. There isn't much I see that should be changed, only upgraded. For example, you may want to look for a necky that has some CD on it too. For me, every percent of CD I get adds about 500 damage. It adds up. Another example would be your bow. See what you can do to get a higher damage calamity. I know they are expensive, but it is one of the things holding you back. Consider getting CD or AS on your litany ring too. Other than that, basically just keep working on improving your dex. Your hellfire is pretty nice for exp, but as far as DPS goes, a nat's reflection would be far superior (if you get one with CD or CC on it). You'd get similar DPS with the ring itself, then slap another 130 dex from the set bonus and you'll be over it. It might not be a huge difference in all honesty, but you're getting to the point where gains are small and expensive.
Kyokei hit the first thing I was going to say right on the head. That's a ton of dex you're missing out on. Being a dual wielder, you're missing a huge part of most people's vit (DML), so it's going to be even harder for you to make it up. For that reason, I'd suggest you really work on your eHP and vit. While I understand that appeal of 4 piece nats (used to use it myself), I tend to suggest otherwise. These days, you can get good mempos with high dex and vit that will give you a ton more DPS and eHP than your nats sight will. Take a look at the one I found in my sample build. That was 5m or less and gives a ton of eHP (and more DPS than your sight). While it's true you'll lose the disc, I don't think you really need 50 if you build your character right. I've gone with 38 disc and find that I have no trouble surviving (I can facetank most MP10 elites) and my eHP isn't spectacular. In fact, my sample build has nearly the same eHP and only costs 75m to build.
Long story short, I'd suggest you move away from 4 piece nats. Consider getting some dex on your ammy. Also, I'd suggest getting shoulders that have AR on them. You definitely want to do that. I would seriously consider trading out your dawn for a DML. It will give you a bunch of the vit that you need and will (most likely) increase your DPS substantially. Try simulating it though. Also look into getting a calamity with a socket. That's a huge source of DPS you aren't currently taking advantage of.
Once again, kyokei hit my next point perfectly. Your CC is hurting right now. I know you get a 10% bonus with archer, but that still doesn't compensate. To take advantage of night stalker (which I suggest you start using), you need good enough CC so that it procs frequently. By increasing your CC, you'll no longer need SS and can use a NS.
In summary: more vit, more CC, more eHP, better weapon, consider DML.
Thank you! I appreciate the feedback. I'd love to give it a look, but it seems you're on your WOW profile. If you could either post a link to your diablo profile or repost here with your diablo profile I'll be able to take a look.
Edited by Genesis#1518 on 12/3/2012 10:21 PM PST