I have had a lot of fun with the Soul Fragment cards in this last set.  The fact that they are autocast gain 2 health makes Suicide Warlock a little less suicide-ey.  

This is a pretty straight forward deck.  Just run and gun.  The Felosophys help to buff up your Flame Imps and Fiendish Servant to not only make them a little more nasty, but potentially give you an additional minion in you hand.  Having a buffed Voidwalker or two can also be a great help.  But even if you cast it on Spirit Jailer with Outcast, you're getting 4 Soul Fragments and 2 2/4 demons on the board for (1) mana each.  It is just an all around good card.  Even buffing up the Nightshade Matron is a boon, there isn't a downside to having it in your deck. Not to mention, if you punch your opponent in the face for at least 4 damage, the Frenzied Felwing becomes (0) and tossing Felosophy on that could give you 2 4/3 demons for free that turn.  The possibilities with the card are amazing. 

The Darkglare, Neferset Thrasher, Life Tap, and Diseased Vulture combo is just too good to leave out in a Suicide Warlock build, so they go without saying. What I am excited about this deck is finally being able to utilize the Pit Lords I've had for years.  These T3/T4 beatsticks always came with such a heavy price that no one wants to run them.  But in this environment, you can easily toss them in and feel good knowing that you have a few Soul Fragments to help you out in a jam.  

The Flesh Giants are just a good slam in the face and give the life manipulation of Warlock a very happy boost. Especially if you toss one to Expired Merchant and end up with a few more heavy threats that your opponent will HAVE to deal with at a low cost. 

I have been wondering if tossing in Brittlebone Destroyers for the evasive and taunt minions, but I have not encountered much to this point where they would need to be slotted in.  BUT, should you play this deck and find yourself encountering evasive minions and/or taunts that you cannot Soul Shear or just plow through, I would say trading them for Frenzied Felwing wouldn't be a bad choice.  

Enjoy the game play!