Fabien asked a good question in the comments to the last post -- what happened to Headgear and Masks? Discussion to follow the jump.
My thought is that Headgear and Masks (and Glasses) will all be sets of items under the general "Head" slot.
In 2.x, you could only have one set (or "genre" as I called it then) loaded for each slot at a time. So you could have either Headgear-Aliens or Headgear-Modern loaded, but not both. That resulted in a lot of aggravation when you wanted to have eyeglasses AND a face mask AND a hat AND a helmet all loaded at once.
So in HM3 you'll be able to have all of those loaded at once. So when you click on "Head" you'll see a list of all (for example) seven Head sets that exist. For the sake of argument let's say they were:
You could have none, one, three, or all seven of those sets loaded at once. And you can load as many items from any of those sets onto the figure as you want. So you could have two items from Mask=Standard plus one from Glasses-Standard plus the basic head shape from MaleHead plus three items from Headgear-Military. All at the same time.
You also don't see things like separate listings for Leggings and Overleggings and Pants for the same reason -- those are going to be sets of items you can load into the Lower Body slot. I'll also have them broken down where appropriate into the sub-slots, so you can have one long flowing pant leg on the right Thigh but not the Left, or a glow on the Left Shin but not the Left Thigh, that kind of thing.
Making all of that work and still be easy to use is definitely a challenge. And I'm putting all this together as we speak, so it's certainly possible it'll change as I go, based on your feedback and suggestions. For instance, as I am typing this I am trying to imagine if it'll be too frustrating having to choose to load in both Heads and Headgear, and trying to put the right Dupe setting on each in order to be able to control them all, etc.
It's a balancing act, to be sure, and one I'm going to have to tweak a lot to make it work properly. Lots of beta testing to be done, you lucky dogs!