I'm going to go ahead and provide the "raw stam view" just so you have someone from each side's opinion, and you can draw your own conclusions. I will say though since paladins have a higher natural EHP pool than warriors, at high gear levels they can easily get away with matching stam bonuses with avoidance gems.
But in my opinion in most fights the things that will kill tanks are things that are unavoidable, and thus you must be able to just take them to the face, be it impales, biles, stuns, freezing slash, etc. Therefore it is best to stack EHP (armor and stam) since those are the only things that can guarentee survival. Also for the most part healers can keep someone up through "normal damage" regardless of their avoidance since tanks get plenty from gear right now. A lot of people roll with gear with 2 +9 socket bonuses and 1 +12 socket bonus. Lets say they hit the +12 socket bonus (for meta), if they go for the +9 socket bonuses also they drop 12 stam for 10 defense and 10 dodge.
After buffs and depending on armor levels, that 12 stam is roughly 300EHP that goes towards you surviving a hit that can kill you versus an extremely small percentage of avoidance that doesn't contribute at all to preventing or surviving any of the damage that will be delt to you based on that special unavoidable attack capable of killing a tank.
So... that's my 2cp, however even at almost the exact same gear levels as our pally tank he has well over 4khp than me fully buffed so gemming some socket bonuses to pick up a slight avoidance gain isn't necessarily a bad thing, but I also have about 2.5k more armor than he does, so.... /shrug.
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