If they are taking a lot of spike damage it's one of two things: either their gear is really really bad, or they're getting hit in the back. When I see a tank continuously turning their back to groups of mobs I'll politely ask them to position mobs in front of them. It reduces damage considerably. Damage mitigation based on percents is meaningless in low level dungeons and practically meaningless in level 50 dungeons. To me a good war was very easy to heal through content like AK. (before 2.1) If they were getting hit in the back though, well forget it. Paladin I could somewhat manage despite bad tanking but a WAR tank would drop like a rock.

Or you were in cleric stance.