If you think Petraeus could've overshadowed President Obama, then you have no clue of what you are talking about. Petraeus would've NEVER become president of the United States, it takes more than a biography to become the president. John McCain was a war hero but lost handily to Obama. Petreaus would've never made it out of the Republican primary, the current republican party voters are too extreme to nominate him.
U.S. confirms ISIS computer expert killed in air strike (Reuters)
from the article: Petraeus' resignation will be a loss for Israel, too