Your comment communicates inexperience with Shiradi:
1) You DO get to do helpless damage against enemies struck by nerve venom. At level 20, my Epic Antique Great axe gains a significant damage boost (thanks to sense weakness) to damage on foes stunned by nerve venom (much to my surprise, making this destiny excellent for aura warlocks who can effect an AOE crowd control). Additionally, I am able to clear Epic Elite mobs using Shiradi just fine (even though I must use skill to survive the throngs).
2) Anyone running sentinel with mana will be able to enjoy those same benefits and near invulnerability; it's not that warlocks are overpowered, it's that you're making design choices that nearly get them there because that is what the tree is DESIGNED to do.
3) Care to define what a "triple exploit" build is? Because as far as I am aware, the only exploit builds that are out there now are the monk tree builds with whirlwind strike (able to strike multiple times if I recall the feat correctly), and wolf builds. To say nothing of Fury Monchers who can really crank out the damage if they wanted to.
You also only chose to address one part of my sentence rather than the whole of it (which mentioned Draconic - if you're running fiend/Great old one warlocks, who benefit from the acid/fire spell power. They do quite a lot of damage, and the wing surge is quite effective. Even more so, the destiny's extra aura and acid damage add a nice punch). Legendary Dreadnought warlocks who run in melee spec (like I do with a greataxe) enjoy quite a bit of damage reduction and significant melee DPS boost. Crusader also grants a nice mix of dps and healing (I see them as being in between Sentinel and Angel).
If I recall correctly, Quells can shut down your divine destiny abilities as well (including reconstruct, renew, and more), and they should be more common than they currently are (to make intercession ward items more useful).