Let me start by saying I have been using FCP X for a year now and really love it. We produce a half hour weekly TV series so I put it through its paces on a weekly bases.
I was horrified to return from the holidays to find out that an automatic update yielded a whole new file system. By packaging all of the Final Cut Event and Project folders into a single library file you can no longer access the original media from other programs such as Photoshop and After Effects without making two copies of all of the media. This really cuts into the pipeline. In the past we were able to recreate new show opens and transitions quickly from within After Effects by linking to the original media in the event folders to use them as source files in compositions. The same was true of grabbing frames from Original movies for use in Photoshop for promotional materials. With the use of the Libraries, ALL OF THE LINKS ARE BROKEN. Yes I know you can right click on a library and still view the files, yes they are still there, but you can't do that from within another program.
This Library system doesn't make any sense. Its a step back from the old system. It was much easier, quicker, and efficient to move large event libraries and projects off and on the system and backup using Finder. Now you have to open up Final Cut to do everything and its a lot slower.
I want to appeal to any Apple developers who monitor this to return to the old system of file management.