I do not know about recent developments (thanks for the link, I will read).
However, even if the theory is known for both things, in practice, the technology associated to rockets or balistic missiles is usually seen as much more diverse and difficult to master and more strategic than the payload.
Personnally, I would tend to agree. But I am not much informed in that field (or I suppose I would not even allow me to talk of the topic on a public forum).