here's where I think the BS comes in...
many of the "attacks" that Awlaki orchestrated were the result of FBI entrapment. that's not conspiracy theory, it's fact. (not that the underwear bomber/times square bomber... etc. weren't assholes to begin with.. they were) so if the FBI knew enough about these supposed plans to infiltrate and entrap the perps, couldn't they have just as easily followed the info trail back to Awlaki and captured or killed him any of those other times? these are just my thoughts and speculations.
just my gut feeling: I think this is just another piece of propaganda, another notch on the bedpost for Obama. my mind may change slightly if they come out with concrete proof of the assassination, but until then it's just another "we got him, and then dumped his body in the ocean... just trust us" type of thing.