With regard to the content issues, most of your complaints are a result of a certain popular content creation company turning user hacks into standard op.

Mat poses (mat files as pose files) and mor poses (morphs as pose files) were hacks discovered by users.  Curious Labs did not view them as legitimate.  eFronteir accepted them because many of their late PPP products and up used them.

Hair comes in two forms.  Conforming or figure hair and prop hair.  Prop hair ends up in the hair folder.  Conforming or figure hair ends up in the figures library because it has a cr2. 

Since you are using P7, you are still bound by the rigid Poser runtime library set up.  This restriction ended with P8. 

Zips are common to every brokerage these days.  Including DAZ.