Update:
I ran ramparts at 58 with my newly respecced prot warrior, with probably half outlands gear, and had a bit of a hard time as an off tank. I wasn't able to consistantly hit mobs to keep up the rage I needed to hold aggro. Eventually, my role degraded into the healers personal body guard (which was successful).
Since then, I hit 60 and have all outlands gear now. I am tanking ramps without any trouble at all.
With the outlands gear, I went from 4500 health and 5000 armor to about 6800 health and 8300 armor.