Outside of being able to more reliably fire dirty what else makes the AK-47 the "best"?
I am being serious here as somebody who has fired both AR-15s and AK-47s. The difference between the two platforms is astonishing when you start looking at the ergonomics, accuracy, recoil, and upgrade capability of the platform. Being able to fire more reliable dirty is the only thing I would say the AK-47 wins against the AR platform.
The way I look at it, they're both designed the way they were meant to be used and both fit their intended use quite well.
I remember in the first firefight I was involved in in 'Nam, all the guys I saw on the line were shooting blind over their cover including me, mainly out of fear, but also because with the smoke and dust being kicked up from firing you couldn't see where you were aiming anyway. I blew my whole loadout way before I thought I would and had a panic attack over it right then and there. In the heat of the moment there's no such thing as fire discipline. Well, until you get numb enough to consider it. Funny to think about it now, but terrifying at the moment.
Point being, blind spray and pray was the most common way I saw auto fire being used at the time. Especially after the first zing and thwack came by. In that regard it didn't matter what I was using, unless you figure in how much ammo you could carry and still be "invisible". (5.56 being lighter than 7.62)