Great post, Harper: you hit all the major avatar beauty basics.
I was pleased to see you made eyes your 5th and final piece. It's one that is often overlooked by people with otherwise great looking avatars. You see these gorgeous models and fashionistas with flat, fake, obnoxious eyes, and it brings down their whole look. Great eyes add both realism and beauty, just like any good shape or skin or hair style does.
I think part of the reason you don't see more avatars with better eyes is because, although there are plenty of styles out there on the grid, only a handful of eye designers have nailed that tricky realism+beauty combo that truly brings an avatar's face to life. For the sake of variety, options and individual expression, I hope lots of compellng new eye styles from different designers reach the market soon.
I think too, that because eyes are a relatively small detail in the overall avatar appearance, many people underestimate their value and impact. But don't we all zoom in on an avatar's face at some point when we're checking them out? Just to see details and guage their beauty? It's a natural, instinctive thing to do; we do the same thing in real life, since we are very much drawn to look closely at a person's face, and especially their eyes! It helps us to read people, to appreciate them and connect with them.
So, eyes are important. Make sure you have awesome ones for your avatar. Take the time to hit the fashion blogs and shop around; do your research, just like you would to find anything else to build your beautiful, unique look.