Still doesn't matter. Warlocks still by far and away prefer the other two perks in that tree. It's not because its useless, its just significantly less useful than the other two perks. And that's as a [i]base[/i] set of perks. It's choice doesn't eat up an exotic slot like the Titans helm will.
And if double grenades by far an away are more useful as a base perk..... Yeah. Armamentarium.