With the new RAF groups I'm in the process of leveling (inc a 4x shammy team), I'm actually finding that the majority of my gear is coming from the quests at the start of the instances. since you get the same stuff to choose from for each toon, armor types doesn't seem to be an issue.
Though, if u run 4x shammys then u can always wear leather/cloth. The damage difference isn't noticeable much until around lv80 or above.