I don't like pointing out problems if I don't have solutions. So here's my suggestions for improvement...some of them, if it were I making the calls, I'd scrap the portal, and work an entirely different GUI from the ground up using the same database, and base that GUI off an alternate system that has proven itself in a time tested environment against a comparable user mass, like Soundclick or GarageBand or the Sony Acid site.
First, force flash artists to use audio portal music. Sure, they can utilize whatever music they like, but that music has to be submitted and approved into the audio portal first. This way, you avoid copyright infringements much more thoroughly, and you improve traffic throughout the site and cooperation between the two portals.
Second, the featured artist is much more important than that silly piece of eye candy asshole robot visualization for the top 5...not to mention the fact that your featured artist should be more important than the top 5 most voted on submissions of the week. Switch the two around. And maybe make it so the featured artist is a voted on sort of deal, with a poll in this forum. That's just a personal thing, I believe much stronger in democratically elected recognition than staff forced to bear additional burdens, like finding a good artist to feature that hasn't been recently.
Best of all time...scrap it. Like Mr. Fulp said in his imaged reply to the box man, its a self fulfilling prophecy, no matter how you spin it. Show the top 5-10 submissions for each genre (one iframe, with a dropdown box to select genres), if any submissions are there for longer than a month, remove them from the capability of being on that list.
Do the same deal with the top submissions, for the most recent submissions (iframe list of 5-10 submissions, differentiated by genre, selected by a dropdown box). This way when I'm checking out new stuff, I don't somehow stumble upon a 13 year old american girls idea of what russian polka should be, and people get longer exposure to the viewers that might actually be interested in their style of music.
Publicize contests. Officially organized or not, contests are a huge fuel for the fire in many musicians in this place, and such should be capitalized on, in the front page. Offer awards for these people, and front page exposure. Notice the and, not or. Front page exposure is everything in this place, because when you get down to it the system is FUBAR, the front page is all that anyone could ever hope for as far as exposure is concerned. The rewards could include anything from multiple votes per day, to displaying a pic or banner in place of one of the ads. Its whatever kind of arbitrary, in house benefit can be mustered, but its something that signifies a since of accomplishment and doesn't eat into the websites revenue, because we all know its all about the benjamins.
That's all I got for now. You do those things, it will make life easier for everyone, except the poor sap who gets stuck implementing the changes.