I think the decision re: media standards, and the decision re: fair use images, are closely related. The sweet spot for WP seems to me to be accepting all formats that improve content, recording the encumbered nature of their formats, and actively working to replace any encumbered content with unencumbered content.
It is partly a matter of scalability and efficiency. A new contributor may find dealing with strange new standards and formats a real barrier to contribution. We can have focused groups of volunteers which efficiently convert from encumbered to unencumbered formats, thousands at a time.... but it is far more difficult to efficiently create from scratch relevant content for thousands of articles at a time.
If people are strongly against allowing any encumbered content in the public view of the projects, perhaps we could have a special holding area for uploaded content which does not meet high standards of free-formatting, but could be converted -- providing for a way to indicate via links? that such content exists in association with a page -- rather than disallowing it altogether.
~~~sj~