My review of Kodachrome
One thing I would add to your observations is archival stability.
Because of the nature of Kodachrome, it is much the same archival
stability as B&W negs. My ex wife just sent me a few sleeves of
slides from 30 years ago. The K64 shots look like I took just took
them. The Ektachrome and Agfachrome (I liked the subtle fleshtones of
that film) are obviously faded. The slides were all kept in a dark
box, but under totally uncontrolled temperature and humidity. Only
repeated, long term projection seems to cause any real lose of image
quality with Kodachrome.
Thanks for bringing up the archival capabilities of Kodachrome. Since it is analogous to a multiple layered black and white film, it does have similar resistance to fading. The color was added during processing so there weren't left over color couplers sitting in the emulsion. E-4 and the better E-6 processes require a stabilizer step at the end to keep the couplers in check. Budget color labs were notorious for stretching their chemicals thus causing poorer archival qualities. Surprisingly, the new Ektachromes and Fujuchromes are much better although you still need a good lab.
The older E-4 and E-6 films couldn't handle long term storage very well unless you took extreme precautions. Also, the old vinyl sleeves actually destroyed them even faster.
I never liked Agfa's color film products much. They had grain the size of rocks and a strangely warm color cast. I can see why you liked it for fleshtones. Everyone had a nice healthy glow.
Anscochrome had great greens but not much else going for it.