Every military rifle now in service has shortcomings, even the highly-coveted ones made in Switzerland by magical little elves who live in snow-covered gingerbread houses. I was going to compile a gripe list someday covering all of the ones I am immediately familiar with, but never decided to do it. All it would do is get rocks thrown at me. :D
The short answer to your question is 'Yes', but the can of worms it opens doesn't answer the next question which is 'What should we switch to, then?'.
It's not just the rifle that's the problem. Just about every US small arm currently in service can't hold a candle to what the US equipped our troops with in 1941, with a little bit of 1958 equipment thrown in and a couple of WWII-vintage arms stolen from other countries.
Whatever the rifle is that's going to have the gusto to replace the M16 series needs is to have both optical and iron sights, shoot 1 MOA with a 'glass rod breaking' trigger break, not be chambered in 5.56mm NATO, not empty it's own exhaust into the receiver to cycle the action, have a quick-change barrel, use a rigid and comfortable folding/collapsing stock or be a 'bullpup', be almost immediately convertible for right and left hand shooters, use semi-transparent synthetic magazines, have the same trigger break feel when in auto or semiauto mode, headspace on the barrel, have few parts, be immediately ready to fire after being submerged in water, have a grit/dust/sand-resistant sealed design, be of such a design that it can fill the roles (in a pinch) of 'designated marksman' or 'squad automatic rifleman' or 'personal defense weapon' or 'vehicle crewman' in addition to 'rifleman', eject brass without attracting attention, be easily suppressed, have positive cycling and ejection, a long meantime between parts failures, carry all of it's gear and spare parts inside it, use a three-point 'Ching' sling design, and still be light enough that an average GI can hold it at arm's length for 60 seconds without struggling -- even if that GI is Jessica Lynch.
I've got my own preferences, so I admit that I am biased. Every time I consider designing a new service rifle from scratch in my head that will satisfy most of those demands, I keep coming up with the Steyr AUG-A2 in 6.5mm Remington or some such similar cartridge. That still wouldn't meet the expectations listed above, but it would come close. However, some of the demands would probably never be met with the AUG-A2.
There, I said it: The AUG is the best thing in military small arms since sliced bread -- at least when compared to the others in service.
Watch. Here come the rocks. (*bonk!*) Ow! ...See?
... I think I'd better leave this thread.