I have actually been playing around with a swarm of GMA Blood Carvers. Cade is an interesting choice, I'll try him out. I honestly like having an Ng'ok in there, too. He's got the same potential damage output of a Blood Carver, and it helps if you get stuck against Yobuck. The squad still rolls over to Lancers, but hey, most swarms die to both Yobuck AND Lancers. This only dies to Lancers. Improvement!
I think the last build I had was this, minus Cade and adding an Ng'ok, Lobot, another Blood Carver, and some trash.