Will Roon provide the ability to filter/Foucs and create playlists and bookmarks based on ALL the
Declared ID3v2 frames?
Thanks 
More, definitely. All, probably not. From a product standpoint, we would accomplish this by importing the data into our data model, and then supporting focus/etc based on that data.
Part of the set of metadata improvements we’re currently working on are about bringing much more data into the system from that various tagging formats, to provide a better experience for people with groomed collections or collections that don’t match up to our metadata sources well.