zdps gear check please

Armory: https://us.battle.net/d3/en/profile/Sarcastic-1984/hero/65374036

Maybe I've missed something really obvious but I feel so much squishier than I should be. I only barely got the set put together so it definitely isn't perfect but I'm sitting at ~70 mil toughness without buffs. I saw a video of a gr100 clear where a monk had 618 mil at the end without his buffs up! He had a shout buff from the barb for 20% armor and 30% dodge but I feel like I'm still missing literally hundreds of millions of toughness that doesn't seem like it'll come from gear optimization. What am I missing?

This'll be primarily a 2 man build with a wizard pushing as high as we can go.