For a while I've seen people saying that stamina DK's have incredible sustain, but I just don't see why that is. What do stam DK's get for heavy sustain that other classes don't get as well? The only sustain skills/passives I see in their tree is Ferocious Leap (ult), spiked armor, & the obsidian shield line. The last two of which, the shield doesn't last long enough to really count as sustain.
WIthout vigor & rally, what other sustain does a stam DK bring to the table that I am not seeing?