Never played a warrior but i do play a druid off tank, not very well
Basically i just got to the druid defense cap which was 415 iirc, i think its 490 for warriors, then started stacking armor and agility for avoidance i imagine warriors have other stats to worry about like shield block values and such but im not sure.
Just to let you know that druids don't need any extra defense they changed our talent so its 6% up from 3% crit immune, which means we need to stack dodge/agi and stamina.