suggestions:
-I seriously hope that the respect/treatment of the members is quickly addressed.. major priority
-Moderate the forum or pull it? Ask for volunteers?
-surely there is a way to accommodate artists outside the US? (taxes,etc). Other sites have achieved this..
-I've tried to look at the pros and cons from different perspectives, there's no way around it, uploads need to be moderated and approved. This addresses the copyright, quality, and cut down on the abusers/spammers. It will help artists know specifically what's appropriate content. It may take a little longer for uploads to be processed. We've had to deal with that before.. Someone mentioned volunteers, I was thinking the same thing, and if they get an additional %, that much better of an offer.
-Base payouts on Downloads, not views. Some of us check back occasionally on our uploads when someone posts a comment. Not all views are downloads.

The tiered idea..

New/newbie upload section with no payouts? Content deleted  x-amounted days after no new downloads

Pro upload section from new upload section 'graduates'.. content upgraded to Pro when content provider has x-amount of downloads, then payout?
..that gets a little tricky, factoring in what's a good 'graduate' number.  Average the high and lows of each section and decide what is ideal for Pro section amount of downloads.. ??