Expanding from warflock

Just finished building the spearhead, and I love every model except the shaman. I'd like to build up a little force of these dudes.

But where to start? I love everything about the ogroid thaumaturge, so he's happening, but I'm not too fussed about the kalric acolytes (not weird enough, at first glance anyway). I'm also probably focusing on the mortal side of the army at least to start with. What units and/or boxes should I be thinking about?