“Without small atomic warheads, ballistic missiles are not practical weapons.”
The Nazis were working on nuclear weapons. IIRC their initial estimate of warhead size would have been within the limits of the V-2/A4 payload (1000kg). They also had the standard arsenal of chemical and biological weapons.
And who’s to say that if the Allied bombing campaign hadn’t been successful that we wouldn’t have resorted to missiles with HE warheads?
Because ballistic missiles with HE warheads, especially with the accuracy of the V2, are ineffective weapons. They consume more resources to build than the damage they inflict.
German nuclear efforts were ineffective and half-hearted at best. The Germans spent more money on the V-Waffen than the Allies did on the Manhattan Project. The Allies, the Americans specifically, spent more money on radar than they did on the Manhattan Project. It was correctly said that radar won the war, the bomb ended it.
http://www-personal.umich.edu/~sanders/214/other/news/Bethe.html