that quote always bothered me too. there is a big difference between accuracy and precision, and as a trained chemist, i always cringe when i hear obi wan just jumble these terms together. especially since stormtroopers can't hit the side of a barn. it's not exactly 1st order canon, but in the jedi knight pc games the storm trooper blasters are the least precise of any energy weapon you can pick up. it's just accepted, stormtroopers and their rifles can't hit shzt.

also, near the end of the 3rd season of "family guy," they spoof this idea. peter is at a shooting range and next to him is a stormtrooper shooting at a cutout of luke, and missing badly.