Hmm, paladin definitely take less damage than Warrior at high level. xivdb.com and look up paladin skills. Big one is Shield Oath: Reduces damage received by 20%, while lowering damage dealt by 20% and increasing enmity. It's an "always on", like Defiance. Then you have all the extra cooldown ones: Sentinal, Rampart, Bulwark, Hallowed Ground. And the blocks from shield. All put together I expect pally to take a lot less damage.

What warrior does is higher HP and heal themselves somewhat. In a way, it sort of evens out. But it'll be like pally very steady life bar, while warrior goes up and down a lot.

As for Str vs. Vit, I'm full Vit at the moment. It adds 17 HP per vit (510 HP for full VIT at lvl 50). That's roughly 8% of total HP for me currently. I don't really know what % of total damage 30 Str would add. If it's 5% or more, I might go Str instead. But I'm guessing it'll be less than that.

As an "average" warrior, you should be able to tank Garuda and everything else up at least as far as Amdapor Keep. Maybe even all the way up, but I haven't been there yet to say. Think of warrior as the "hard mode" of tank: you're a bit harder to heal, but you bring more DPS to the table. And it's not *that* bad on the healing. I prefer Warrior so far for those reasons.