for crusader that makes sense. i probably be more of a team buffer that is tanky. lots of options here .....
we got a passive where holy damage will heal us...... theres even a legendary potion with the affix increase life per second with a 30 second cooldown....(which i use).

another passive finery gives us str for each gem socket we have in our gear. as str = more armor = more mitigation + offensive dps.

Akarat's champion will prevent the first death blow and restore us back to full life. I prefer that compared to iron skin.

other gear stats to make us survivable are.....
armor = from str or the armor value from gear. mitigates all damage types.

all resistance = mitigates spell damage.

block = depends on chance to block to proc. Will reduce damage based on your block reduction value on shield. Max cap for block chance is 75%

dodge = crus don't even bother, because we don't stack dexterity enough to care about this. We even have a passive that removes the dodge mechanic, for an increased 15% block chance.

hp = your health points comes from a combination of vitality and life% to boost hp further.
life per hit = this is the life steal replacement. it's not as good as the old life steal, but it's all we got as a replacement.

life per second = use this in combination with lph.
there are other less reliable healing stats like..

-health orb heal bonuses
- life after kills
In summary aim for 350k + hp with 14k + armor, with 1100+ all resistance. This is good enough for torment 3 and 4.

The general rule is you want a 10:1 ratio for armor versus all resistance. Mine is 14xx : 11xx and i'm doing okay. I can usually get the remainder from monk buffs, so i'm not too worried about making it exactly 10:1 
dmg mitigation is important but don't neglect your damage either.

my white sheet damage is 1.1m, with toughness of roughly 9.5m