I've redesigned the poster, taking a lot of that feedback into account. It's been tightened up considerably, some of the principles have been changed, the design has been tinkered with, and generally it's been greatly improved by your thoughts and comments. So, thanks!
Here's the new version:
I've also created an entry for it on my online store; you can actually order copies of it now! The poster is 16" x 20" (smaller than the Map of Human Sexuality, which is a monster), and printed on very heavy semi-gloss paper. Barring any major last-minute edits, it will be going in for printing tomorrow, which means I will be able to start shipping it early next week.