So recently I got really annoyed at D&D because I learned how strong real life slings were, and I've just realized that CoC2 gives slings the D&D treatment. Of course it's for balance since it's considered one-handed in both games, but historically slings were not just used for close range (at the upper ends they could be used for firing at targets over a thousand feet away), and I don't think any weapon which fires palm-sized rocks fast enough to break the sound barrier can be considered weak. Admittedly if it's a short sling (so, generally not what a sling that would be used in warfare) then maybe it would be weak and also used with a shield, but historically if you're bringing a sling to war it's long, it's powerful, it has immense range, and you wouldn't even use a shield because the techniques to launch it would be using your whole body and you'd essentially be sniping targets from far away.
But yeah, I'm annoyed that slings get treated as being really weak, short, and inaccurate when real historical slings were powerful, long-ranged, and precise (with the proper training, but without the proper training bows would suck too).