Good points, although I'm not sure I necessarily agree about the buffer tube. I actually PREFER the slightly longer length of the commercial tube, but not adhering to the mil-spec allows some manufacturers to use a lesser grade of aluminum and use less desirable threading methods. On the flip side, I've never actually every seen a buffer tube that has broke that wasn't literally blown up or run over.
The 1:7 twist rate is actually designed to stabilize LONGER bullets (tracer rounds); the fact that they are usually also heavier is dependent on the material.
I would choose my Fulton Armory FAR-15 w/ a 1:9 Krieger barrel any day over an OEM Colt barrel; reinforcing your point that Mil-Spec isn't always better. I view it as the minimum acceptable level of quality.
Colt make a good gun, but there are others out there who've taken the design a step further.
Hk USP 45 Expert, USP 40, USP 9, SIG P226, S&W M&P9, Hk 4, Makarov, Desert Eagle 40, Beretta FS92 Centurion, Kimber TLEII 1911A1, Glock 22, SIG P225, 1943 Rem Rand 1911A1, S&W mod 64, Walther PPQ, SIG P229, Browning BDA 45 (SIG P220), Hk45, SIG P230