I think that's pushing the envelope to expect a peaceful capture of Bin Laden. It certainly could have been worse, one of the option favored by many was to bomb the crap of the compound. Obama chose to put american lives at risk to conduct the operation. One of the reason may certainly have been self serving since it looks a heck of a lot better to have a confirmed kill than a pile of rubble but the less cynical could say that this also potentially limited innocent casualty particularly in the light of the fact that they weren't sure Bin Laden was there.
I really don't see a set of circumstance where Bin Laden would have been captured alive, if the guy comes out with guns blazing, you can't expect the US to back down and walk away. Even though Pakistan authorities couldn't be trusted, they have been allowing the US to conduct operations on their soil and are somewhat trying to outwardly act as an ally.
As for the Tripoli bombing, it is sanctioned by NATO so the US should not be shouldering the entire blame. It certainly could have been an assassination attempt though NATO of course claims that they were strictly targeting military and strategic installation. It is not for us to know what the real intent was and it's easy enough for NATO to hide behind the UN resolution and the possibility that it wasn't intentional.
It is interesting to see aggressive actions being taken once again in an oil rich country under the pretense of protecting the population...Funny that in less prominent african nations, they don't want to interfere with local politics.