If you want to make a gunfex a fun combat monster give him claws (and the venom cannon). Claws look mean and will appeal. Sure you can roll less attacks rather than more, but if you like stealers you are used to needing sixes anyway.

Seriously though, claws are a great deterent, noone will want to go near it.
Even in the metagame I would recommend mace tail for a gunfex, its only 5 points, and if you are based by a unit (the normal way of stopping one) te extra attack will come in handy freeing you.