Overall the big issue is how much did Von Braun and his people (and their equivalents in Russia) actually contribute to the U.S. and Russia. I can say off the top of my head that in the U.S. by 1945 Karl Bossart was proposing the initial design for Atlas (which by including a monocoque structure and proposals for vernier control alone was superior to the V-2 design) and that supposedly the design of the V-2's engine in many ways mirrored Goddard's work on liquid fuel rockets. And, just out of curiosity, does anyone know how much of the technical work that went into Vanguard, a Navy program, or of Atlas, an Air Force program, was actually inspired by work by Von Braun and co., who were located at the Army Ballistic Missile Agency? In the Soviet Union though, based off of Zaloga's books on the topic, the contribution of the German's they had in their employ utterly paled in comparison to Soviet engineers. It's been a while since I read those, so I don't remember exactly how much the Soviet's actually learned in the process of building their own copies of the V-2 technically, but I can say that the German engineers were put into their own design bureau separate for Korolev, Chelomey, etc, and the German design bureau ended up only ever designing two missiles and the best their designs saw were entering into limited production.
Technically, I'd say that the U.S. and U.S.S.R. were both in a position where even a complete lack of German talent doesn't actually harm their missile and ultimately space efforts notably. Their domestic talent was more than capable and was responsible for the lion's share of the work in their missile and space efforts. The far bigger issue for the Soviets would be whether people like Korolev end up getting out of the Gulag system without the impetus for rocketry research created by the V-2, but that is a product of the far greater impact that individual personalities had in that part of the Soviet system as compared to the American military-industrial complex.
