My problem with the assault rifle rounds is that I expect my rifles to be able to do real rifle things. Assault rifles are fine if the situation at hand calls for a rifle dressed up like an SMG. But as soon as you have to turn cover into concealment or reach and touch beyond across the street distances, the assault rifles lose their muster, and their utility. Giving up the hallmarks of the rifle--it's range and power--to achieve greater volume of fire seems rather like shooting one's self in the foot.
One thing the guy in the video forgot or neglected to mention is that the newer versions of the M16 and the M4 aren't even capable of fully automatic fire. Thus you give up the range and power of the rifle without achieving the volume of fire provided by the SMG--you get the worst of both worlds. My mission as an 0311 was defined as engaging individual targets with aimed, semi-automatic rifle fire. The M1A/M14 superior to the M16 in this respect in every way that matters. I would have gladly humped twice the weight to get 3x the effective range and more "oomph" at every range.
Basically, the M16 lacks the range and power to compete with a real rifle and only boast the firepower advantage over the SMGs if it has full auto capability, which it doesn't. It is a self-defeating contridiction of terms--it's like ditching the full-sized Dodge diesel for a sporty little coupe on the basis of speed, then putting a governor on the coupe.
Note also how when it came time to put aimed semi-automatic rifle on point targets at 300 meters or so, with iron sights, the AK didn't seem to have much, if any, more difficulty dropping the targets than the M16. AKs are inaccurate? Riiiight.