Prefacing this with the fact that I don't play this game anymore, so keep in mind that none of my suggestions bear any hidden agendas. I am posting this simply due to the huge investment I put into this game and the Paladin class.
My opinion of easy fixes for Paladins, in order of importance:
Add aggro back to (at the very least) self heals. As any Paladin knows all too well, in EXP groups or Raids, we find ourselves opting out of using our self heals in lieu of casting blind(s)/stun to maintain aggro (becomes less noticable when you acquire Runic 2 but then you have serious mana issues on any long fight or in an EXP group). This is a glaring issue because self heals and ghots are really the bread and butter of the Paladin class, and pretty much always have been ever since our AOE aggro niche was marginalized.
Create a new Yaulp spell line akin to Runic 2. This is an obvious one here, and honestly I am surprised it was not put into the game when I first suggested it to the Dev team. There is really no reason that this would shift the balance between Knights at the lower tiers where people traditionally view Paladins as being better than SKs (despite that not being true). If you maintain the same burst aggro potential to mana cost ratio then it will provide all Paladins a means to snap up aggro more quickly if the MT goes down, while not providing anywhere near the means to consistently generate more aggro than a Warrior or SK over a given fight due to mana issues.
Make blinds un-resistable. This is a no-brainer to me. I can't think of any reasons why Paladins should not have a consistent and effective way to maintain aggro on magic resistant/immune mobs.
Tweak flame of light. I was quite happy when Zaela said that she was changing the flame of light spell. However, as just about any Paladin will tell you, its use is almost entirely limited to magic immune mobs, and the damage is marginal at best. The result is that it is almost never utilized. My suggestion would be to increase the damage and add more ranks (similar to SK spears). This is essentially an idea that I had of giving Paladins 'smite' style spells. To balance this so not every Shadowknight starts whining about us treading on their shoes, restrict the spells to only be cast when equipping a two handed weapon.
With all that being said, none of this would change anything about the intended hierarchy for tanks.
Shadowknights:
Best single target aggro
Second best AOE aggro
Second best mitigation
Second best self-sustain (not by much)
Second best DPS while tanking
Second best raid utility (ability to pull in a snap or provide wipe recovery, solid buffs)
Warriors:
Second best single target aggro
Worst AOE aggro (not by much)
Best mitigation
Worst self-sustain (no spells)
Best DPS while tanking
Worst raid utility (no spells, although some of their stances seem neat on paper)
Paladin:
Worst single target aggro
Best AOE aggro (consistent)
Worst mitigation
Best self-sustain (again, not by much compared to a fully AA'd Shadowknight's lifetaps)
Worst DPS while tanking
Best raid utility (ghot, single target heals, best buff)