It's not all about the model of gun. A lot of it is about consistency of manufacture of the gun and the consistency of the ammo being used.
As far as proving or disproving the stereotype goes, the main problem lies in that consistency or lack of it. I have seen some WASRs that shoot pretty decent 2-3" groups at 100 yds with good ammo (not bad for a short sight radius, a creepy trigger, and not the most precise sights in the world to begin with). I have also seen WASRs that made patterns resembling a shotgun at 25 yds.
I have seen similar performance variation in Hungarian, and Egyptian AK types. I have seen AKs go from 3 inch groups to 6 inch groups just by switching ammo.
Putting a scope on a gun doesn't make the gun itself more accurate, it improves consistency of aiming ability.
If you have shot an AK, like an AK and want an AK, then you should get an AK and not worry about what other people think of them. They ae a fine rifle for what they are. Precision accuracy was never a design priority. The idea was to give the foot soldier high volume of fire in a light weight, reliable package that would provide fighting accuracy at ranges from close to contact out to 300 meters. It will do this.
If precision accuracy is what you seek, then I recommend a bolt action. There are a lot of gun designs because there are a lot of different specialty jobs that different designs do better than others.