I've been testing PLD/WAR differences on Lv. 58/59 Grass raptors in Corenthas (these have a strong spammish 700 damage fire attack and hit for an average of 300 physical damage without any defensive buffs; they are basicly mini Ifrits).

With the proper skill utlizations and combinations, I hardly received any damage and managed to maintain my hp at ~80% on PLD. By the end of the fight I had roughly 70% of my MP (which I beleive to be excellent after a 3-5 minute fight). PLD's major mp gain is cover (an ability only useable with atleast one other person in the party), which means you lose out on mp gain while solo. PLD would lose out on DPS because they have better actions to perform which actually allows them to survive such as stoneskin, cure, etc. (which still generates enmity), not to mention timing your abilities and attacks for maximum hate/survival which may also dampen their damage over time.

Now on warrior, I did all I could to survive. I zerged my HP regain moves and tried to keep defensive buffs up. I managed to kill some of these monsters; I was generally left with 10% hp on most fights and I died/evacuated 1/4 of the time. Warrior would deal more damage in a solo situation because killing it faster is the only means to your survival and it's really all warrior has to utilize.