There is only so much you can do to an ak, before it starts to mess with reliability, and ruggedness, and still be an AK. Everything gets a return, whether advantageous or not. I have several AKs, beyond a light, and optic, there are no other real changes to the design.
One thing that many forget, is the calibers contribution to the guns reliability. General Kalashnikov did not approve of the change to 545x39. Typically, the longer and skinnier the round is, the more difficult it is to feed. I have had an Ak in 556, and had reliability issues, I have 2 in 308, and they have hiccups. My 762r guns never fail, ever. Gun is the same, caliber is different, pressures are different.
the ak 12 i think has fallen into the AR and AK thing.
I am not a big fan of Jim Fuller, but, he is correct on the ak............rearward of the rear sight block, the gun is perfect and should be left alone.
further more, not a big fan of Herrera, funny, but not really in on the info if you know what i mean. He brings up the "westernized" way of holding the gun, this is completely untrue, and based on the internet thought process of competition based tactics in combat. The truth is, they are not really compatible, can be, but usually not.