I only played my warrior and paladin up to the upper 20's, but I can say that though my Paladin had a higher armor, my Warrior definitly did more damage, could absorb more damage and could hold aggro MUCH better.
Now perhaps I am not like most people and in my hands the Warrior outshone my Paladin in terms of playing tank. But I really doubt that is the case. Because frankly, I doubt I can do better than most at playing a class.
True a Paladin has a few nice spells, but a Priest/Druid has much better versions of these spells and a smart Warrior always has a Priest/Druid near. Paladins are tougher to kill, but in a group scenerio (which is what I think of when determining tanking skills), this benefit carries over to the whole group.
In a group with a Paladin, Warrior, Priest, Hunter and Mage. The only difficulties I had holding aggro was when the Mage over-cooked the mob. There was no way the Paladin could take aggro from me, if I was determined (and I usually am) to hold aggro.
Paladins are nice, but we have to snap out of our perceptions that are colored by other games. Warriors are going to be the best tanks, that is what they do. Paladins are going to be the best at giving the group-wide buffs, that is what they do.
Each class has something they are better at than all the other classes. Or else there would be no need for different classes.