Yes.
Any being truly worthy of a God Emperor title would have transformed their entire population into their children, into primarchs, but if he had turned all of Earth into a population of primarchs, the entire cosmos would be totally conquered within 2 chapters, and you'd have nothing to moan about.
As we saw in the first nail of the coffin, with the initial betrayal of the thunderwarriors, the writers aren't up to the task of imbuing the emperor with the amount of charisma needed to fully and wholly recruit every being and saving every soul, reducing the initial grand, if whimsical, scope of their story from a true messiah level portrayal of miraculous levels of science-wartime leadership and reverting it to the far easier slapstick minutiae of 'ok lets just kill everything'. It is a genre that caters to the understandably retarded monkeys of this planet, while leaving the more benevolent warmongers wishing for more.
At the very, very least, the emperor would have given every human the ability to regenerate from life ending wounds, but uhh, I guess that isn't grimdank enough to sell plastic figures to manchildren.