Looks like we are running into the same type of comparisons that WW2 pilots made. Everyone has anecdotal evidence showing that one type of weapon is better than the other.
The M-16 is one of the most accurate assault rifles made. I have seen charts listing the mil accuracy compared against other rifles. Its been a long time, but if I remember correctly, M-16s fresh from the factory shot 4-5 mils, while other rifles like the Styr Aug shot around 10 mils.
Using the proper ammunition and full length barrels, the 5.56mm round does produce massive wounds against unprotected bodies. As we all know, when an assault rifle round enters the body, it flips 180 degrees and travels backwards. This is because the bullets center of mass is shifted rearward due to the aerodynamic shape of the bullet. An AK-47 round for example, enters the body, travels a short distance, flips 180 degrees, then exits the body. A 5.56mm round enters the body, begins to flip, but breaks up into several pieces, all causing substantial damage.
But I agree, with our army being made up of citizen-soldier teenagers, we need a reliable rifle that is more suited for urban combat. The M-16 failed the soldiers of Jessica Lyndes convoy. I certainly don't believe that they weren't cleaning their rifles either. Who goes to war and neglects their rifle within the first few weeks?
Seems like most people agree 6.8mm would be a good round. But how about a rifle that will fire with sand and grit? It wouldn't need to do that many times, just enough to get people out of an emergency.