I think Fitz's focus all along has been to "get" Rove or Cheney. Why else has he persisted in this idiocity? Scooter just isn't worth it. At the very least he gets to embarass the WH as Scooter tells his story.
I think you've hit it.
This has been Fitz's pattern with all the corruption trials here in Chicago (all convictions btw). He starts small and works up.
That's how he got ex-gov Geo Ryan (RINO-maggot), is now working up to Mayor Daley, and our ijit Gov Blago (Dem-nice hair) along with the Dem controlled Cook County Board.
He even uses that tactic with the mob - starts with a 'button man' and works up the food chain. The Chicago Mob is 'almost' wiped out thanks to Fitz (that's a GOOD thing).