Whoever “Raymond Davis” really was, he is out of Pakistan now. The interests of justice have not been best served, but this is far from the worst possible outcome.
The most disastrous of outcomes would have been for Pakistan to accept Davis had diplomatic immunity. By agreeing to pay blood money the US have de facto dropped that claim. To accept that an evident mercenary like Davis had immunity would have made a mockery of the Vienna Convention, and ultimately eroded the security of all diplomats worldwide, and especially US diplomats. Davis was never a diplomat and we can be confident he is not going on to supervise textile negotiations or public diplomacy in Denmark. It was a farce and a disgrace that Obama ever made that ridiculous claim.
Another very bad outcome is that Davis could have been hung. Nobody deserves to be hung. If you could make a world ranking of by how much people do not deserve to be hung, Davis would not score too high. But still, nobody deserves to be hung, plus blood is becoming the currency of politics in Pakistan. We have to hope nobody connected with his release is assassinated.
The payment of blood money entails an acceptance of guilt. It would have been better if his self defence plea could have been tested in court, but he has dropped it and acknowledged guilt.
Personally the payment of blood money for murder is a bias towards the rich which is one of the many things I find unacceptable in Pakistan’s system of sharia law. But the Americans have taken it, and in doing so have indicated their acceptance of the justice and validity of sharia law, which is one to chalk up for future reference.
So my own urge for proper justice may not be satisfied. But I am not a party to the case and it appears that Pakistani law has been followed. So as I say, not the worst outcome.