What you have here is HP Recovery vs. Mitigation.
Now if you are only taking Mitigation into account here, yes PLD trumps WAR quite soundly.
Now lets look at HP recovery. PLD has only two real tools to aid to this purpose. Cure/Convalescense, Bloodbath/Fight or Flight.
Warrior has Defiance...yes Defiance.
If a PLD and a WAR both have 4000hp, a warrior in defiance has 5000hp. You might think 'Oh that is just buffer hp and once it is gone the PLD has the edge.' To which I'd say you are wrong. Remember, when it combat characters naturally regenerate 2% of their health every 3 seconds. So that 1000hp difference translates to 20hp every 3 seconds the PLD is not getting. That is a free 400hp a minute for doing nothing.
Then you have the big hitter, Inner Beast. 300 potency 300% heal based off the damage it does. And it came be used roughly every 13-20 seconds. (Twice in a row every five minutes with Infuriate.)
You also have Storm's Path which also has a potency of 300 (after you factor in the 20% boost from Maim that combo's into it.) And it heals for 50% of the damage dealt...every five seconds. (And gives 2 Wrath stacks towards using Inner Beast again in the process)
Then you have the wraith stacks themselves....that while up add .3% bonus to all healing spells cast on you as well as GLD's Convalescense. (Also at .2% bonus to crit chance which boosts healing from Storm's Path)
Then you have Thrill of Battle which is a straight 20% heal/health buff. Great for an emergency heal and even better to use at the start of a battle or even prior to a casting of stoneskin from your friendly WHM.
And then you have Second Wind. Which now works quite wonderfully with Berserk which in turn works quite wonderfully will most of the above means of healing.
And then you have Blood Bath.... which is 30 seconds of free heals off the damage you do. Which is in turn aided by the stacks of wrath you have as well as Internal Release (for a quick boost to 30% crit rate not counting stats or gear).
Oh and almost forgot about Mercy Stroke. In a one on one fight this move is not much but in a fight with adds. Even though both classes have this skill the hp recovery is capped to 20% of your max health (so again Defiance means a bigger return.) and WAR's can use it 30 seconds sooner.
Needless to say a WAR will be recovering A LOT more HP than a PLD ever will. And while PLD's cure is not that bad, it has two real big short comings (and no its not the amount of the heal!) The two biggest short comings of cure is 1. It sits on the GCD AND has a cast time... which means that is a good 5-6 seconds of inactivity. Which leads to its second short coming. Cure has very poor enmity values. Meaning a PLD who is curing themselves is a PLD who is not doing damage or generating hate. Turning PLD's cure into a more situational tool than one that sees regular use. This means that while a PLD does mitigation much more damage than WAR the damage that it does take it will NEED a healer to get it back effectively while a WAR who doesn't mitigate as much damage has much more adequate tools to recover that lost HP so in the end it balances out.