The reason for the "There are no tanks for my dungeons" is the same reason as in every other MMO. The number of DPS vastly outnumbers everyone else, and tanks that are on usually do their Duty roulettes, and that's it. after that, if they need myth, it's usually a party finder group doing brayflox speedruns until your eyes bleed.

A warrior has more HP, because it doesn't have the defensive capabilities that the PLD does. PLD has block, parry, b-20% damage received, and blind. PLD also has an amazing skill called Hallowed Ground. WAR just has parry, ('cause let's face it. Holmgang is only good for its' binding capabilities), but has more HP and DPS to make up for it.
Until warrior puts on defiance, both jobs have pretty much the same HP. That being said, I still prefer PLD on speed runs because the mobs usually die before I lose agro.

I hope this helps. Not trying to discredit your experience or anything, just adding another point of view.