Comes down to really this, I've honestly never found room for the guy. He's 5 points which cuts out room of an arc node, while the AP is nice, it can only be done a single time, and while indeed mobile, over all to me it just seems like we have better things available for the points..
That all said/asked.. ..I've been looking through our own jacks as to what weapons would be nice with the Cankerworm, eating out own.. ..is there any people prefer?
The Harrower's Perisher doesn't seem bad, though it's only P+S 12 on the Canker, taht's still reach and Thresher which can take out a good number of troops. It's Mortifier not being too horrible as well if you want something shooty.
One 'big' one that stood out to me was actually the Slayer's DeathClaw.. ..seeing as the wording for the special attack doesn't really mention you needing two at all, it sounds like you could combo strike with it. The Claw being POW 6, giets you to P+S 14, and 20 on the combo strike.. which would still be better than the AP of his other weapon, in many cases. (Of course Nightmare's Wicked claws being even better, due to adding in reach.)
Levi's Gun wouldn't be too horrible, same Rat, and now gives you a very mobile and stealth firing platform, guns having no loss to the damage of the shots.
Gave thoughts to the corrupter, while I think Cankerworm might get better use out of it's weapons than the Corrupter itself.. still not worth taking the Corrupter for such.
Well, those are the only one's of ours that stood out to me, I'm curious how people use this model to decent effect.