Is there a sentencing angle to federal prosecutor purging?

In today's New York Times, Adam Cohen has this Editorial Observer asking "Why Have So Many U.S. Attorneys Been Fired?".  Cohen's tentative answer is politics, but I find more intriguing Jeralyn's speculation here at TalkLeft that "prosecutors' views on the death penalty may be a factor."

I feel bad personally for the former US Attorneys if their firing is simply the product of broad political dynamics, but then I cannot resist suggesting that these fired USAs now understand one aspects of being a defendant and defense attorney facing federal sentencing.  I often spend time explaining to federal defendants and defense attorneys that sentencing judges and appellate panels may (sometimes?  often?) be influenced by various political forces far beyond their control.