This doesn't sound right somehow.
Terrorists have to be killed; terrorism had to be wiped out, by whatever use of force that is required.
There is no doubt about that.
Where the whole thing seems immoral is when the methods used are equivalent to state-sanctioned murder, carried out by the organs of the state.
Is this what you want? Decisions taken by self-appointed groups on whom to kill? Decisions taken on the basis of evidence that is found sufficient or insufficient depending on individual thought processes?
Just to work things out, what if tomorrow the President decides that for the safety of US troops, nobody is to be left alive in a 20 KM cordon sanitaire, a belt parallel to the Durand Line? How will the decision implementation differ from today's drone policy?