A totally dedicated folder is not appropriate for all products. It requires judgement.  The OOT Hairblending products all use common textures, so not keeping these textures in Textures is not appropriate for this method.  For OBJ and textures that are used by multiple figures, the traditional method using Geometries and Textures is better.

On the other hand, Roxie skate boots - both cr2 can live in the same folder with their OBJ.  And, Roxie herself - unlike Dawn or V4, her OBJ already is in her Libraries folder.

Having in Materials mt5/mc6 that are useful for multiple figures or props is appropriate.  Not having these buried under a bunch of poses that are only for individual products  - they are easier to find.  

For hair,  all can be in Hair even if they are cr2 or pp2.  2nd party hair texture add-ons and their poses are easier to find and use if they are in the folder with their hair product.  Those with prop extras - the props can be in the folder with the hair they come with.  If it is something that you want to use for other things, then keep them in Props. 

If you collect characters, they are easier to manage with one folder per character with the textures, Mat poses, and morphs.  In my case, I spawn a single head morph and single body morph for each character and keep them in the folder.  Once done, the !Ego folders with morphs can be deleted (just keep the original zip somewhere, just in case).