This was tough... Warlocks are engines of power, and to make sure that they are balance, you have to take all their abilities into account in all situations. Not that this is any different from the other classed, but I had a harder time judging Warlocks.
ANYWAY! Below are my thoughts on improvement to be made to Warlock gear to make them all the same level of awesome and a viable choice in any situation.
Heart of Paxic Fire - No change
Discipline and/or Strength or Intellect
Improved cooldown buffs from Radiance.
Skull of Dire Ahamkara - No change/Better description
Discipline and/or Strength or Intellect
Take significantly less damage while Void Bomb is initially activated, and improve all Drain effects.
Apotheosis Veil - Buff/More Utility
Discipline and/or Strength or Intellect
Immediately Regenerate ALL Health and improve Weapon and Movement Speed for a short time after Super Activation.
Sunbreakers - Buff/Significant change
Intellect and/or Strength or Discipline
Solar Grenade duration is increased, and grants the Touch of Flame perk.
Light Beyond Nemesis - Buff/Large rework
Intellect or Discipline and/or Strength
Revive allies Instantly, and ability kills drop additional Orbs of Light for allies.
Voidfang Vestments - Buff/Significant Change.
Intellect and/or Discipline or Strength
Provides an additional seeker to Axion Bolt Grenades, and provides the Soul Rip perk.
[b]Edits have been made to the original post...
I REALLY don't know what to do with Apotheosis Veil... Health Regeneration is cool, but it need more universal utility. [/b]