@Grumpy Gnome
The M4 is not inherently less accurate than the M16A2. The reduced site radius (roughly the same as the maligned AK) makes it less accurate in actual use than the M16A2 when using irons only. As pretty much laddy doddy everybody has an optic of some sort, the two weapons are equally accurate.
Reliability of the M16A2 was initially a little better than the M4. But M4 feed ramps, improved ejector springs, etc., have made the difference negligible or nonexistent.
The handling as you noted is greatly improved. I have a 1SG buddy who has a Signal Company with a number of smaller statured females in it. That company recently turned in their M16A4s for M4s and had a radical improvement in qualification scores. (Bear in mind the qual now incorporates standing, kneeling, and barricade). Amazing what you can do with a weapon that fits.