As a music artist this one affects me personally, so I'll just go through this list one-by-one and try to offer fixes that better match up with what I believe to be the spirit of the rules.
- As a Music Submission - Users may not upload original copyright renditions of audio. Covers and karaoke-style submissions are permitted tracks provided full credit is given to the original performing artists.
The wording needs to be more specific. I presume your intent was to block uploads of copyrighted material that the uploader neither owns nor has permission to upload. However, the current wording would block the upload even when the user owns the copyright, or has permission from the copyright-holder to upload it (commissions where the author retains the copyright for example). Only public domain pieces would be acceptable with this wording. Suggested fix: "Users may only upload audio for which they own the copyright or have verifiable permission from the owner of the copyright. If it is a public domain piece, uploader must be the original author of the track. Covers and Karaoke are permitted provided full attribution of the original performance is given." Rationale for the public domain restriction: there is no need for everyone and their mother to upload the same piece of free music, and this was the best way I could think of to prevent that.
- Samples and Remixes- Remixes are permitted, but significant work must be done to distinguish it from the original copyright material.
This is a bit vague but there is probably nothing that can be done to fix that; this will be one of those rules that will have to be set more on precedent than on its wording. I trust this will not be abused.
- Mashups - Mash-ups are only permitted when one half of the mash-up contains user-created material.
This rule bans mashups by the definition of a mashup. The "user-created material" of a mashup is the mashup itself- the selection of which music to use, what parts to use, and how to order them. The music itself is not what the mashup artist creates, and fair use laws account for where the line is to be drawn between mashup and copyvio. A simple "Mashups must adequately comply with the fair use provisions of copyright law." should be all that is required; the actual fair use provisions can be applied and used to determine what is acceptable and what is not, there is no need to duplicate them here.
- As Part of a Flash Submission - Music may accompany Flash files as a part of Fair Use. The music must compliment the content of the Flash, not merely used as a means to upload full tracks.
This rule is fine as-written, but the wording feels a little rushed and unprofessional. Try this: "Flash Submissions - Music which is not owned by the uploader and has not been granted verifiable permission to use may only be used in a flash submission to the extent afforded by the fair use provisions of copyright law." The corollary to this rule is covered by fair use provisions and thus does not need to be mentioned here.
Closing thoughts: I believe the problems people are having with these policies is that they aren't written as policies- they are written as guidelines. Policies are the actual rules and they need to be as specific as possible in order to avoid collateral damage. Guidelines on the other paw simply compliment and help explain the policies- these can be worded more loosely because their words are not law. Splitting the policy into a strictly-worded and highly-specific policy document with an accompanying guideline document that explains the spirit of the rules in the policy document should help alleviate almost all problems people have with the new policy. I think that we all agree with your intent with these new rules, we are just concerned about the loose and unprofessional wording that causes too much collateral damage and seems to be miles away from the spirit of the new rules.
Thank you for taking the time to read my post.