Let me start off by saying, I love my Paladin and playing it. But it's so obvious why there are so many complaints. I won't stop playing my Paladin, but I can see it's biggest flaws as well.
So I couldn't help but wonder. What is it that REALLY makes Paladin's fall behind the other tanks? There's the usual argument of less DPS, but then what really makes the other tanks better?
Each tank has their enmity increasing/defense buffing tank stance:
Warrior: Defiance learned at lvl 30
Increases maximum HP by 25%, while lowering damage dealt by 25% and increasing enmity. Increases HP recovery via curing magic by 20% for self. Also increases chance to hit by 5%.
Dark Knight: Grit learned at lvl 30
Reduces damage received by 20%, while lowering damage dealt by 20% and increasing enmity. Also increases chance to hit by 5%.
Paladin: Shield Oath learned at lvl 40
Reduces damage received by 20% and increases enmity, while lowering damage dealt by 20%. Increases accuracy by 5%.
So first off, the other tanks get their increased enmity and damage reduction tank stance at level 30 while Paladin's get it at 40... However, Paladin's get their offensive ability at lvl 30 while Warrior's have to reach lvl 52 after entering heavensward content. But even without the warrior's offensive tank stance, they still can produce more damage than a Paladin. You'd think that maybe they'd at LEAST give Paladin's (who are supposed to be damage soakers) more DEFENSE at the very least in their tank stance.
Now for the offensive tank stances:
Warrior: Deliverance at lvl 52
Increases damage dealt by 5%. Effect ends upon reuse.
Using certain actions while under the effect of Deliverance will grant Abandon. Each unit of Abandon increases critical hit rate by 2%. When five units are stacked, you will become Uncontrollable.
Dark Knight: Dark side at lvl 30
MP is slowly drained while increasing damage dealt by 15%. MP refreshing statuses have no effect.
Paladin: Sword Oath at lvl 30
Increases the potency of auto-attacks by 50.
Although the warrior has to wait until heavensward content and it's a lvl 52 (22 lvls higher than the other 2), their offense is already pretty decent and this is a decent little boost to add on. The dark knight get's a whooping 15% increase at the cost of draining their MP. Honestly, sounds fair. Then we get Paladin. Increases auto attack potency by 50. Better call the ambulance's now folks... Come on SE. Not even gonna give us Paladin's an overall attack % buff like the other 2 tank classes? If this increased our auto attack's speed rate significantly as well, I wouldn't mind, but it's just a simple add on to the current auto-attack. Yes, every bit of extra damage helps, but come on.
Now aside from the stances that are very against Paladin's already, if we take a look at our enmity producing attacks, we can also see a significant difference. I'm not going to list everything here, but let me point out one of the big ones (imo). Every tank class's bread and butter for gathering up quick mob enmity is their aoe's.
MDR/WAR
Overpower: Delivers an attack with a potency of 120 to all enemies in a cone in front of you. Additional Effect: Increased enmity.
Level: 12
CD: 2.5 sec on GCD
TP cost: 120
Steel Cyclone: Delivers an attack with a potency of 200 to all nearby enemies. Ignores the 25% damage penalty inflicted by Defiance. Can only be executed when Infuriated. All Wrath is lost when used.
Level: 45
Additional Effect: Increased enmity
CD: 2.5 sec (but requires full infuriate)
TP cost: 0
Dark Knight
Unleash: Deals unaspected damage with a potency of 100 to all nearby enemies.
Level: 8
Additional Effect: Increased enmity.
CD: 2.5 sec
MP cost: 9-796 (lvl dependent)
GLD/PLD
Flash: Increases enmity in all nearby enemies.
Level: 8
CD: 2.5 sec
MP cost: 8-707 (lvl dependent)
Circle of Scorn: Delivers an attack with a potency of 100 to all nearby enemies.
Level: 50
Additional Effect: Increased enmity
Damage over time for 15s, Potency: 30 (combined total potency of 250 per target).
CD: 25 sec
TP cost: 0
Now at first glance, these seem pretty decently spread out. Warrior and Paladin's both get 2 and Dark Knight has 1. All have an AoE that does damage. However, this is actually quite deceptive.
Warrior get's 2 attacks located on their GCD of 2.5 sec that both do AoE damage (and both fairly potent).
Dark knight get's 1 attack on their GCD of 2.5 sec that does avg damage.
Paladin get's 1 non-damaging move on the GCD of 2.5 sec. Circle of Scorn can only be used ONCE every 25 seconds. Sure, it does a good combined potency of 250 when you add in the DoT, but do you know what this means? It means that for Paladin's to hold enmity on a group, they have to give up damage. They could use circle of scorn right off the bat, sure, but tell me, how many Warrior's and Dark knights do you see that use only 1 overpower or 1 unleash to grab a large mob's attention. Heck, how many times do you see a Paladin only use 1 flash? And god forbid we enter a dungeon under level 50 with a PLD. We lose our AoE damage to keep aggro.
Now, to make matter's even worse, flash is a cross class skill for ALL of the tanks. Paladin's can use it. Warriors can use it. Dark Knights can use it. Everyone can use it (though it's questionable whether or not Warrior's should even bother with it. It's a decent back up incase you run out of TP, but most learn to manage TP better as they progress).
But Paladin's have provoke! Oh wait. That's also a cross class skill that EVERY tank can use. Well, I'm sure that Paladin's cross skills are very useful... Let's see:
Foresight - Foresight sounds great. Basically get another Rampart. Cool. Extra 20% dmg reduction for 20 seconds.
Skull Sunder - sure, why not add in another move that provides no benefit to the class whatsoever as it's part of the GCD and doesn't have the ability to combo (sarcasm).
Fracture - DoT. Ok, not bad.
Bloodbath - Hey, you get hp back! Not as great as a WAR who can hit a bunch of enemies at once, but w/e! It's health!
Mercy Stroke - if I can time the kill just right, I can get 20% hp back! Oh boy! That won't be hard when there's a party of 8 slamming away at things!
Cure - Hey, healing! Paladin's are supposed to be support healers, right?! What?! 200-250 hp per heal? That's at a low level right? Oh. Level 60 huh? Well, what if you stack all your attributes into mind? Oh, 1 mind basically gives +1hp heal since PLD's get no magic weapons and there's almost no decent gear for Paladin's to increase mind... Seems great.
Protect - Hey! That's useful! Who doesn't like more defense! Oh. You almost never get to use it in any party because it has a healer who does. Well, at least you can use it if you ever want to!
Raise - Woah. Raise?! That's awesome! You can raise people during fights who drop!! Oh. You're not allowed to raise people in battles unless you have a trait to allow you... Then when do you use it? Oh. After the battle. That seems nice...
Stoneskin - Sweet! Stoneskin is amazing! And it actually is awesome! Now, what other sweet cross class skills do PLD's have? Oh. There's no more?
Well, you got Stoneskin and Foresight that are awesome... um. Bloodbath doesn't hurt. Can you deal a good amount of high damage or constant quick damage? Oh. Well, like I said, doesn't hurt to get more hp. Uh, Mercy stroke can give you a good chunk of hp back... if you time things right. Uh, and last.... uh. Why not fracture? Because. DoT. There. 5 aweso... well... extra skills.
Well, heck, I mean, I'm sure Warrior's don't get anything good either, right?!
Wait, what. They can use all good skills from pugilists?
Featherfoot - Dodging is increased. That's nice.
Second Wind - Wait, they get a move that heals at 450 potency based on Strength?! But Warriors are all about strength! I mean, the rest have to be sucky!
Haymaker - That can only be used when you dodge an attack! It's like PLD shield swipe! That sounds like it could be great in combination with featherfoot. But I'm sure it's on the GCD, right? Oh, it's not. Well.... that's actually pretty sweet. And it slows target's down. Damn.
Internal Release - That only increases critical hits. I mean, who even care's about doing more damage. psh.
Mantra - That only helps with HP recovery. What would a tank need with that?! psh. Oh. And it also effects party members within 25y. Oh. That's pretty sweet. Well, the other cross skills probably suck! Oh. They're yours from Gladiator. Ouch. Uh, I mean, they didn't get that much better stuff than you (._.)'
I'm sure Dark Knights cross skills suck then! Oh... they just gave them all the tank cross skills. Well... PLD's sure sound like something!
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Ok, I'm done being sarcastic now. Big question on everyone's mind. How to fix these issues. Balance seems off. Changes were recently made to PLD's but they really didn't add that much. Shield swipe was the biggest effect that came and, well, that helped a little bit, but not in the whole. It allowed for PLD's to deal a bit more damage and an extra move off the GCD to help with enmity. The biggest problem though is, you are dependent on waiting for a block. Our stun move (shield bash) is still on the GCD, meaning we can't use it whenever we need and we have to interrupt our combo's to stop attacks on time otherwise unless we got lucky with the timing.
I know that we won't get any additional cross class skills. It's too late to add that. I understand the dev's probably won't go that route. We could add on new moves to try to balance things out, but then everyone will cry for more moves. I wouldn't mind it, but I have a feeling it's just not coming unless they raise the level cap again (but hey, maybe).
So instead, why not fix this through new gear? We introduce new gear every patch anyways. Heck, it probably wouldn't be too hard to alter some pre-existing gear either! Why not bring back what it means to be a Paladin in most games. They are supposed to be heavily armored knights with both armor and healing magic at their disposal. They were supposed to be both tank and support. If a Paladin could pull off an 1200+ hp heal, then they'd be useful. Heck, even an 800 would at least be decent for stalling (in terms of lvl 50 sync dungeon content). Give paladin the ability to raise people in battle. I don't care if you make it a lvl 60 trait for them. But doing this would make Paladin's a VALUABLE asset worth losing some DPS over. A Paladin that could actually sustain themselves a bit incase the healer goes down or just to give a healer breathing room to heal other's from a large AoE attack from a boss.
Sorry for the long post.
TL;DR
Instead of trying to make PLD match up to the other tank classes in DPS, why not give them their own individuality that makes them an asset. Give them gear that boosts mind and piety more and choices for magic based sword weapons (so all the healing potency isn't lost). Give them the ability to raise in battle to actually be an asset to the team in a dungeon that matches their title. We gave PLD's cure and raise, but they are so useless because we have no gear to allow them to take advantage. They are instead, wasted slots in the cross classing.