You have the right selection of gear but, just not the stats in some of them. Unfortuneately you've also rerolled the wrong stats but the build below will help you correct it.
Off my head
Hellfire Amulet, or any amulet, needs +physical % dmg and CHD + socket. Hellfire is only good if it has a crazy passive. Otherwise, use something different.
Weapon - I find that Life per fury is crazy good. When you jump 3x then boulder toss, back to full HP
Wrist - mandatory +physical % dmg
Then make sure you always leap into combat, there's not much trick to this build. Always leap, keep shout and cry on cooldown. Toss to empty fury and lower cooldowns. You shouldn't be getting one shot at GR68. Limitation of this build is damage, not survivability.
Great point Jideo. I would also inform that the earthquakes from leaps and whatever can be spread around because they continue hitting for a few seconds. Especially helpful for large large gruops, you don't need to stay in the one spot jumping. I recall having 600k Hp aswell at around your level.
You should be able to do 70 with that gear though you need better cloves IAS doesn't help this build it should have Str, Vit/Cdr, crit, crit, your hellfire is spot on for this build, you need to have a combination of 40%+ cooldown reduction and 180 fury to reset your leap after a boulder toss.