Alyssa looks at the possibilities:

Now, long-time readers know that I have a long-running interest in the Star Wars extended universe, and in fact screwed up my promise to finish reading the Yuuzhan Vong arc of the books and blog them (though I got a couple of posts done). So when it comes to the prospect of an extended universe television show? I have opinions. And this strikes me as a bad way to go about making a Star Wars television show that will capture the imaginations of people who grew up with the original trilogy but have had their tastes honed by The Sopranos and The Wire, among other things. 

The thing the Star Wars extended universe has done quite well at is filling in the world around the Skywalker family and the people who have married or been adopted into it. Lucas, particularly in the prequels, is rotten at this. He'll seize on an idea, be it crabby, potentially racist frog-people; slug-like gangsters who haven't been couped for no particularly discernable reason other than who wants to be the biggest crimelord in a backwater; or feral teddybears and run with it. He's got a sentimental streak a mile wide and absolutely no sense of how institutions work. For Lucas, politics actually do happen in the Republic's Senate chamber, and mercenaries ultimately come around to the nobility of democracy promotion. 

If you're going to do a Coruscant-crime-lords-meet-a-consolidating-Empire storyline, and you're going to do it with existing characters, that probably means a show about Prince Xizor taking over Black Sun and mounting a rivalry to Darth Vader. Which is honestly, just another Powerful Dudes Duke It Out story, rather than an institutional one, even taking into account the whole Vader's bioweapons program killed Xizor's whole family thing. Vader and Xizor aren't actually surrounded by anybody interesting, and focusing a story on them would be sort of arid and weird, and wouldn't actually reveal anything about the impact of Imperial rule.