Oh lordy, I just Vassaled a minions list a few days ago (I finally got my Minions book), and goodness gracious you guys have a mean warlock in Bloody Barnabas! The list I ran was 50-point T4 Barnabas:
Ironback Spitter x3
Gatorman Posse (full) x2
Bog Trog Ambushers (min)
Wrong Eye + Snapjaw
I was running up against a T4 eKreoss list with a metric crap-ton of Exemplars, Gravus, Fire of Salvation, Daughters etc. I was pretty worried about that many WM infantry models, immune to both continuous corrosion and KD, with my pretty low model count going into the game. I had first turn, and after both of us moved up the field, I used Warpath to get all three Spitters in range of Gravus, and took him down. After that it was a constant threat of a drop-and-pop on eKreoss, combined with the nice control ability of Swamp Pit to really limit my opponent's options, and the effect of his feat. After some back-and-forth skirmishing between our infantry, I popped my feat, brought in my trogs, did some trampling and shooting, and the game was swung pretty heavily into my favor. We ran out of time, unfortunately, but I feel pretty confident I could have sealed the deal.
With the combination of his scary melee prowess; control, protection, and mobility spells; and a wicked feat, I feel like Barnabas is a pretty righteous model. Anyways, I just wanted to say congratulations on having such a great warlock! Your options might be limited right now as a faction, but at least they're limited to mostly radical models!