It's nice to have an accurate, hard hitting, and reliable rifle.
But without the suppressive fire to help acquire those targets, it becomes a whack-a-mole contest.
Heavier ammo, smaller capacity (20 rd) magazines, and the sheer weight of the average soldier's battle rattle will limit the utility of the rifle in suppressive fire situations. It's a step back to the M-14 in that regard, and that led to the development of the M-16 and M4...
The 5.56 round still has a place in that suppressive fire role. (M-249 SAW, for instance).
Make 'em duck, take 'em when they pop up.
Full disclosure: I have never served in the armed forces nor carried a rifle in battle. My understanding of small unit tactics comes from talking with vets and a lot of reading.