I would really like your feedback and extension to the ideas here to help us decide the best path:
Feel free to add new ideas to the document or just reply to this discussion.
Current file manager and file picker is not compatible with subdirectories in file areas. Listing of files is relatively easy, the tricky part is how to choose where you want the picked file to land. Depending on what type we choose we might have to implement it in both file manager and file picker somehow.
The Current files is not a true repository plugin because it may also allow write access and file management. I think it should be also visually separated from the repositroy plugins which allow only read access. I agree that the current files section does not always make sense - it should be enabled only when useful (multiple files allowed)
The popup file manager could be also linked from the filemanager formslib element. I guess that could solve the subdirectory issue, unzipping, etc.
I think we should implement both full current files support in picker and also pop-up file manager. The text editor integration should be flexible enough to allow multiple image plugins installed at the same time. Administartors could define several editor set-ups and users could then specify which set of plugins/icons they want or even switch set-ups on the fly.
What do I vote for? Combination of B and C and at the same time giving contrib developers an option to create new A image plugin easily. Users should have an option to specify their own preference too.
I think this adding-plugins-approach is the best way to go if we want to be able to update TinyMCE regularly in the future. The pluggable editor system that Petr added allows also different configurations for several editors with different plugins so we don't necessarely need to have / show same editor plugins for all users.
Moxiecode itself (team that made TinyMCE) is using different plugins (Ajax based interface using a JSON bridge) for filemanager and imagemanager in addition to standard image and link plugins that can be seen and tested in full version demo http://tinymce.moxiecode.com/examples/full.php