My biggest want is being able to manually assign where projects and render files are stored, regardless of where that device may be.
This demand seems to be popping up recently and I hope it comes in the next major update, and I believe the solution is bringing back sequences and making FCPX similar to the Aperture Library.
The major issue has been the removal of Sequences from FCPX and the separation of Events and Projects. I really think Events and Projects are the same, but Events pertains to family videos and Projects pertains to clients.
FCPX says Projects are FCP7 sequences, and I want to see them restore Sequences (creating a Compound Clip is a FCPX Sequence workaround). Make sequences depended of client projects/family events with the ability to have multiple sequences per project/event such as a wedding video, highlight reel, menu page, etc. I can't stress to Apple enough that the Project Browser Window/Folder should be merged into the Event Browser Window/Folder and Sequences would be found in the dependent client project/family event. This is how FCP7 worked and it worked extremely well having all dependent media and sequences centralized in one location.
Examples:
user/Movies/Client Video Library/Client(s)/Project(s)/Sequence(s), Auto Saves, Original Media, Render Files, Transcoded Media...
Ability to have multiple clients per library, multiple projects per client, and multiple sequences per project. Dependent Auto Saves, Original Media, Rendered Files, Transcoded Media, etc, would be found in the project folder.
user/Movies/Family Video Library/Year(s)/Month(s)/Events(s)/Sequence(s), Auto Saves, Original Media, Render Files, Transcoded Media...
Ability to have multiple years per library, multiple months per year, multiple events per month, and multiple sequences per event. Dependent Auto Saves, Original Media, Rendered Files, Transcoded Media, etc, would be found in the event folder.