When I learned Poser had this flexibility now I re-organised to an exent similar as above, but made consideration of portability. 

Hair for example is usually easily converted between figures. Wardrobe Wizard does for short hair, and for the large base of hair pieces for the Victorias there is HairConversionSystem. For the purpose of a single scene, some transformations and an odd magnet may suffice. I do not want to go trough all my figure runtimes to find a hairstyle I like, so I simply made one Runtime dedicated to hair content. I go in there to find what I want, convert if necessary, and store along with the basic hair. Each hair 'product' has its own folder, in which there are the content files for the different figures. There is also a sub folder for the textures. 
I kept this hair sector as a separate runtime to keep the overview. To be done: Listing of the various 'fit-morphs' that are already included.
From Poser point of view hats, caps, glasses and earrings or any headwear are not different from prop hair and may come out well with the same transformation techniques, so I consider consolidating that too.

The adventure with hair worked out very well. So, encouraged by the success and the ever improving clothing conversion tools: (Wardrobe Wizard, XDresser, Fitting Room) I did same for clothing items and made a clothing repository Runtime. Here too items have their own folder with versions and materials. Also, all prop auxiliaries are merged in. So, if the set came with a matching umbella or optional bow, it is all in one folder.

Likewise, figure based environments find themselves with their auxiliary props, lights and camera settings each in their own single folder.

This is an ongoing project, of course, with progress depending on the need of the moment and my level of irritation with the old setup.

The good thing about this work is that when having all this pass trough your hands you find jewels you had forgotten about. It is also a way to economize on your purchases, first of all because you no longer buy things while you in hindsight already had, somewhere, something similar, and also because the old stuff gives you plenty of inspiration and possibilities. Load Posette, let EZSkin and subdivision have a go on her, put her a few minutes under the morph brush, render her with indirect light and you will be surprised what she can still do for you.