Won't let me post links, but the last bit of the battle net url for my page is /d3/en/profile/Vuxra-1773/hero/3419164
I've been farming act I for ages, and I've had a few lucky legendary drops. I recently used all my gold to buy a nice Skorn with lifesteal and intellect. I'm up to just under 60k dps unbuffed and 120k EHP before blur/archon. I can do act II easily with archon, but I can't seem to get act III down without a lot of deaths.
What gear should I be working on? What would I need before act III becomes a viable alternative to act II as far as speed and ease are concerned? and what farming routes are good for archon in act II? I've been just running the three zones before Zoltun Kule and then killing him.
To farm Act 3 with Archon, I'd recommend 70k dps to be able to facetank elites with Life Steal and Archon beam, but if you want to see where you stand, just switch from Prismatic Armor to Force armor until you get around 300-400k EHP in Archon. You can also drop blur while using force armor because it'll be useless. I like using Galv ward for extra life regen and longer armor durations.
I'm just over 80k dps with about 170k EHP outside of Archon form, which is about 240k or so in Archon and with 5.8% life steal I can pretty much face tank any elites as long as I move out of desecrator, arcane beams, and don't get frozen.
As for gear, I'd start with upgrading your bracers. You should be able to get 150+ Int for fairly cheap and that should give a decent dps boost. If you get an Adriel's Visage, you could really raise your dps by a lot but you'll lose a lot of your EHP to do so, which might not be worth it until you get more EHP on other pieces. You should be able to get more Int and an extra socket on your pants, plus more EHP either in the form of resists or vit or both. You can probably get a chest with same dps but more EHP also. These suggestions are meant to be relatively cheap, not spending more than 1 mil or so per piece if you're patient enough.
If you are looking for pricey upgrades, I'm really liking my Zunimassa 2 pc bonus. The bonus damage on the boots is about 5k dps more than I'd get with boots that just have the same int and the 130 int from the 2pc is worth another 5k dps or so but the pieces cost me a bit over 40 mil total. The Witching Hour (legendary belt) is also insanely good and would probably give you 8-10k dps but they're pretty costly.
Literally all your pieces can be slowly upgraded one after another according to what you currently have.
For example, your gloves could use more int, higher crit damage. The vitality there is a bonus, which is nice. Your chest piece could use far higher int. Don't sacrifice the all res, you really should add high vitality to that as well.
Your jewelry pieces are somewhat lacking. Start incorporating crit damage into it first before worrying about attack speed (most expensive).
If you want to run Archon, you will need higher, sustainable DPS. I am not sure if you can pull that off efficiently in Act 3 as of now. You might want to consider AP on crit for your helm (or move to 1-hand + source) and play with Arcane Orb or CM/SC as an alternative. If you really want to stick to Archon, better buff up that crit/IAS, and more effective HP.
It's funny you mention the Arcane Orb build, it's what I was using to farm up the gold for Skorn. I switched to Archon because it lets me farm act II really fast. I tried CM a while ago, but I didn't like it.