Hello, in order for your Force Armor to work properly you need to have enough HP to prevent you from getting oneshotted, in this case FA(Force Armor) will take care of the rest. I can also recommend getting the cap of movement speed, atleast somewhere around 23-25% since it's playing a huge role in the whole kiting mechanic. Lacuni Prowlers is a nice pair of bracers which gives you quite a bit of movement speed but also a nice amount of attack speed which seems to match your playstyle since that's basically what you're going with (and so am I actually).
Personally, I think that gear is great if you could get your HP up to somewhere around 30-35k. The problem may be in your build instead of gear as that's pretty common. We all pretty much get oneshotted, you just need to find a really good stratergy to kite, and here the maximum of movement speed takes its part.
Try different builds and I'm sure you'll knock these dreadful minions down to the ground where they belong! This gear is definitely more than enough.
#Tips for movement speed gear;
Hammer Jammers (Legs)
Talisman of Aranoch (Amulet)
(This is cheap gear, there's much more expensive ones out there if you're rich).
Good luck, and let's hope that someone else will also reply which might include something that will find the solution to your problem!
I've had a several problems throughout my time progressing at Diablo Inferno. What caused those problems is that I did the common mistake, to follow other people's playstyles which means that I basically used their builds. I've tried every single mainstream build and nothing did seem to work out for me. (Please note that I didn't have that great gear because I believe in that you can accomplish almost anything without the perfect gear. Now I'm not saying that gear doesn't matter, because it has a huge impact and is playing a big role on this fight).
One night I sat down and convinced myself that I wouldn't go to sleep before I had killed him. After 3 straight hours of trying, I was close to give up for the night. But then I decided to give myself 10 minutes of where I would brainstorm and take advantage of everything I've learned and seen from the fight of these 3 hours. I came up with my very own build, and it won't suprise me if you think It's weird. I decided to choose the safe way with my build, as there's really no enrage timer on this boss (correct me if I'm wrong?)
The result after my brainstorming was this:
Explanation: My only damage source was the Hydra, and I have to admit he did an amazing job. At first I thought It'd take ages to kill the boss, but it actually went quite fast. I had around 40k damage.
I had enough health for my force armor to work properly during the whole fight. I thought Crystal Shell was a waste of a skill slot because it barely absorbs anything, and It's necessarily not needed. Instead I used Frost Nova incase that I would fail during the fight and the boss would teleport to me, in that situation I would just freeze him and run/teleport away. If you're not close to any wall the boss won't teleport to you, but in phase 2 (The black phase) It's kinda tight of space, so it could happen that he would teleport to me, and here the Frost Nova saved me. I used Magic Weapon and Familiar in order to max my damage out and Teleport just because it makes everything eaiser and can save you from a tough situation.
Please note that Mirror Image may be a good choice to use instead of Magic Weapon/Familiar or Frost Nova. When used, it removes any debuffs on you which is really good, since Diablo can put one on you. If you're not using Mirror Image and you'd happen to get this debuff, make sure to fast teleport to a health pool and zip it and that'll also clear the debuff.
Point of my build: With the build that I used, there was no reason to not move all the time. Basically I had no signature spell or anything like that, the Hydra did everything for me so I could just run and run. By doing this, I was guranteed to never fail. I just ran around the place all the time but not close to the walls so that he could teleport. I'm actually honest when I'm telling you that I killed him on the first try with this build. I had never even reached P3, yet I managed to do it on the first time with this build. I'm not saying It's good, and I'm not necessarily recommending it. I'm simply telling you to try it out because it may work for you like it did for me. I'm just that type of guy who stands and cast my signature spells until the very end when he's about to reach and attack you (You may call it DPS horny). And with this build I had no reason to, I was just always on the run, the hydra did everything for me, and I could just invest my time on avoiding everything without having to think about anything else.
Slower? Sure. Safer? Hell yeah.
Stats: Around 40k health. Somewhere near 40k damage. And close to 2,10 attacks per second. I normally have around 2,80 attacks per second but I had to drop some in exchange for vitality this time. And yeah, as I've understood the Hydra does benefit from your attack speed.
TL;DR: You have no signature spell, you invest your skill slots in abilities which will maximize your damage. Such as Magic Weapon and Familiar. You use Frost Nova incase that you would fail and run to close to wall and Diablo will teleport to you. You use the Hydra to do all your damage. You use teleport to get away or just in short terms simplify everything for you. With this build you have no reason to stand still, and you will constantly be on the run which makes it easier to avoid everything. You have nothing else to focus on but to avoid things. Let the Hydra do the job, and trust me, he does a ton of damage no matter what you think.
Edit: I almost forgot to tell you, movement speed is playing a huge role on both this build and the whole fight overall no matter what spec you're using. I used 24% extra movement speed where 25% is the max. I suggest having a minimum of 17% movement speed. I had Hammer Jammers (Legs) which gave me 6% extra movement speed. I used a pair of random rare boots which gave me 12% extra movement speed. And at last I had Talisman of Aranoch (Amulet) which gave me an extra 6% movement speed. All of these items are fairly cheap and I didn't pay above 200k for any of them.
Good luck and may you seek victory in this build my friends!
Remember, the key to victory lies in your own head. Do not necessarily follow other people's build like this one, but instead try and figure out what works for you.