Sight radius on an AK is nearly identical to the M4... their just a little farther from the eye.
The main limitations are the short sight radius and very basic short-range sights, the short stock, and the goofy/noisy safety with its loud clacks and Safe- Full Auto - Semi positions that require your firing hand to manipulate.
The main blessing of the AK in the hands of the average bad guy is that if the first round doesn't hit you, you're golden, because the rest are somewhere up above you. It also makes a very recognizable champagne-cork pop that makes finding your opponent simple.
The AR family is mostly stuck with a marginal round and easily damaged with its plastic stocks and flimsy aluminum receiver. It also has an inaccessible chamber, which becomes important if something gets stuck in there, and a gas system that funnels burnt powder products into the bolt, chamber, and the firer's face, particularly if you add a suppressor. It is, after all a "least-bidder" weapon.
The best compromise would be the SIG 556 or the Galil which use the AK action and steel and have redesigned thumb-operated safeties. Still stuck with the Mouse Gun 5.56mm though..