Even if the Army does nothing more to improve the M4, the service should be applauded for its decision to dump the three-round burst setting. It's ineffective, never used and hinders accuracy with its inconsistent trigger pull.
But switching to a full-auto setting does raise an interesting question -- does the infantry need full auto when most battle-seasoned veterans -- including special operators -- agree that semi-auto fire is highly effective for suppressing the enemy?
I can't really see a downside to it. Back in the mid-1980s -- before the shift to the M16A2 and the three-round burst -- active-duty infantry units kept to a strict rule that rifleman only fired their M16A1s on semi auto. Today's combat-experienced infantrymen are even more disciplined.
Having a more consistent trigger pull can only help rifleman shoot more accurately.
Hopefully the Army won't ignore the full-auto setting the way it did the three-round burst. It could be a useful tool in certain situations, but only if the service devotes the training time and the ammo needed for units to become proficient at controlled, full-auto fire.