1. WIS is pretty much useless for tanking (unless fighting a magic user and they should be a breeze).
2. Paladins can get +defensive skill from their fighter avoidance buff.
3. Defense skill is the weakest of all the avoidance skills.
4. Magic and Divine are the 2 easiest attainable resistances in the game.
5. It gives +15% mitigation without making you take a big weapon skill penalty.

Have a really close fight you need to win? A few tricks

1. Start with your offensive (wrath) stance up and use all your combat abilities.
2. Then hit your defensive stance twice (once to cancel the wrath stance. A second time to bring up the defensive stance).
3. Wait until most of your attacks at back up and then switch back to the offensive stance and mash all your combat abilities again.
4. Keep doing this until the mob is dead.

The above works well because you are attacking when you in your offensive stance (more damage) and recovering while you are in your defensive stance (more defense and resists).