If the Collections feature in Plex ever gets implemented as several feature requests suggest, I think #1 would be taken care of.
The Movements idea of #2 actually is provided for in the ID3 specification. Plex just needs to implement support for all 3 Title tags, and this would be done.
I’m not clear on what you described in #3 and #4, but it seems like the Collections feature I mentioned in response to #1 might apply.
