Why don't you like the rounds? Stick-n-Shock seems to me to be exactly what Dunkelzahn was asking for in his will when he offered money to the person/corporation who created a non-lethal weapon useful at mid-range. THAT is why I like it from a setting standpoint.
Each to their own.
For me - doing the 'good' thing in SR is rarely easy. It's a nasty, messed-up place. Not killing people is the 'good' thing to do. Its also often the rational thing, sometimes an absolute imperative, although I digress slightly there.
Ergo, I don't want not killing people to be easier than killing people. It's not how I like to run games and its not what SR is about for me. Stick 'n stun, for me, falls on the side of too easy. Just switch ammo and use the SnS and people drop just as quick. If not quicker. Its quite likely its what was already in your magazine already, particularly if you like pistols and automatics, which at a guess most runners do. Certainly in my games. Alright, yes, if you're using an assault cannon its a fall in power, but that's hardly the average runner's average armanent. Or at least, not in my Shadowrun.
Although I have to say the idea of someone using an assault cannon for non-lethal takedowns tickles me pink. What on earth would such a runner use when he wants to actively take people down, twin-linked autocannons?
Aaanyway. Enough silliness. SnS doesn't make them sweat enough if they want to not kill, to put it shortly. Even with its chance of accidentally killing someone. There's plenty of options that will (be it in terms of reduced power, high cost, requiring an unusual skill, accuracy of a Civil Service statistics report and so on). So I, after consultation with my players, ruled that they would use them instead, and that SnS didn't exist.
That is just me and my take on the universe. Others are no doubt equally valid, possibly even more so; you make a good point that there are no doubt companies out there trying to develop like technologies with Big D's will (although they're not there yet). But they won't be reaching fruitiion in my SR anytime soon.
Hope that makes sense.