Last thing I thought about was FFXI. If you look at the skill sets it's quite obvious.
WAR:
#1 Vengeance- Returns damage to enemies and reduced damage. This is a god to a crowd control tank.
#2 Collusion- Pretty much ensures that War keeps hate on a group of monsters.
#3 Steel Cyclone- Probably one of the best AoEs in the game right now. Extremely high burst damage make it so that you can gain burst hate and it can heal you up by a great amount, especially in a larger group of monsters.
PLD:
#1 Holy Succor- Increases sustainability of the PLD and targeted DD/Healer. This wouldn't be used as often when there are trash mobs since they would die fast anyway.
#2 Divine Veil- 100% block rate for 33% of the time. Pretty much makes PLDs very good against strong AA monsters, pretty much bosses. Also gives an AoE Regen which, if melees were more useful in current content, would be great to keep melees alive.
#3- Hallowed Ground- Just compare WAR's 15 minute skill to PLD's 15 minute skill. One is for burst damage (enmity burst) while the other is for sustainability.
However right now since content is all ranged DD, there is no need for a PLD since WAR can do everything better than a PLD especially if there are no melees that need taking care of. I mean Defense is barely important against bosses(for tanks), but it makes a huge difference against trash mobs. This is why WARs and PLDs have almost the same defense. That defense can decrease monster damage by 25%-50%, but against a boss it mainly affects AA which in the end only shaves off around 10% of the AA. I don't think WAR itself needs a nerf, I think PLDs need to be able to tank better (Innate Damage Reduc?) and make it so that bosses are deadlier versus the tank with its unavoidable abilities/AA.
Flash is the only AoE which PLD gets, and the amount of ENM it gives is good for an instant hate gain that will last until the first hit, however WAR can just pop collusion and the first hit will count towards them in hate.