They're like halfway there with him. His background is really cool, but what you'd need is;
Preternatural Senses: Ignores all negative modifiers when rolling to hit with his blowpipe (if he can't even hit his target, what is the point?). I'd also make him ignore armour saves, he's supposed to be a master sniper.
Master Poisons: 4+ to hit causes a wound. 5+ is still way too unreliable.
Price reduction: 100 points. That way, there is a reason to take him over a Skink Chief (with full magic gear, a Chief costs slightly more).
Unlocks Camo Skinks as Core: From there, I'd keep the same price on Camo Skinks, but give them 5+ poison. That makes it a meaningful choice for the player; regular blowpipes are cheaper and more easily spammed, but Camo Skinks wound more reliably and can Scout.