I understand the argument for not giving Hassan the martyrdom he seeks. However, I think it more important that we demonstrate our system and values operate consistently, especially in the face of challenges from outside. If the judgment is for death, so be it.
And yet the morals/ethics/values that drive our system call out for not allowing him to get away with politicizing his criminal behavior.
In a kinder/gentler time, when dealing with folks who differed only in the scale of of their crimes, the choice facing those convicted who had served in the military of the defeated enemy was between being shot or being hanged. Hanging was selected precisely because it was not the option institutionalized (on both sides) for criminals who violated the military law. Lining war criminals up and executing them via a firing squad would be recognizing that they had acted as soldiers. Hanging them signaled that they were common criminals (as far as that meaning can be used to differentiate between soldiers who violated their military oath and the rules of war and whatever it is you call what they were).
Hasan has said that his crimes will not be completed until he achieves martyrdom. Also, others who believe in jihadism believe that after he is martyred he attains honor and should be held up as an example of faith and of behavior to be emulated.
From a political as well as a moral point of view I would rather see him incarcerated and cared for/protected from reprisal by misguided individuals. That protective custody will mean 23 1/2 hours a day by himself in a cell with access to books and tv somewhat restricted (nothing celebrating martyrdom - I understand the Koran is not the source of much of the "philosophy" behind driving folks to matryrdom) would give him plenty of time to contemplate his failure at the last moment. It also means he and his behavior will not be held up as something to be copied.
As for the economics of the matter - it is one time I am willing to let DHS claim terrorist attack attempts were defeated. Who knows, they might be right.
stay safe.