Warhammer 40k all humans are significantly upgraded. How will they do in war now?

[Tyzuris]

So every normal human turns into an Astartes. Every Astartes turns into a mid-level Primarch. Every Primaris Astartes becomes a top-tier Primarch. Every normal human psyker becomes a librarian. Every librarian becomes as strong as Logar or Magnus.

Assume all humans are fertile and able to produce offspring as strong as themselves.

How will humanity do now against the forces of Chaos and Xenos?

 

[Chaos Marine]

The problem with this is you're assuming that a large portion of humanity wouldn't become even more vulnerable to the sway of Chaos and there's a second Civil War that would absolutely destroy the Imperium in a psychic war that could potentially create new Chaos gods. Just because people are suddenly ridiculously more powerful, psychically speaking, doesn't mean they're going to make good choices. Or as good as those choices could be from 40K.

Said Civil War 2: Psychic Boogaloo, will either result in the genocides of the Eldar (possibly) and the Tau (definitely). The Necrons will go "Fuck this," and either release the C'tan from their pokeballs or go into hibernation for another couple of hundred thousand years. Most likely they'll accelerate their waking up and attempt to eradicate all life in the galaxy. The Tyranids will be attracted by the giant psychic flare and the main body will arrive to eat what's left. The Orks will continue as they have been.

 

[CarlManvers2019]

As @Chaos Marine essentially said, there’s the problem that even the Primarchs were human and vulnerable to human mistakes and personality flaws like ego and bias

 

[PsihoKekec]

How does humanity procreate now? Astartes are sterile.

 

[CarlManvers2019]

How does humanity procreate now? Astartes are sterile.

Also, I think the females would like males from below the neck until you see that they don’t have dicks

 

[Tyzuris]

How does humanity procreate now? Astartes are sterile.

By ROB removing their sterility.

 

[DarthOne]

Warhammer 40,000 fanboi’s because even more incredibly obnoxious for a start...

(The misspelling is intentional)

 

[Shipmaster Sane]

The problem with this is you're assuming that a large portion of humanity wouldn't become even more vulnerable to the sway of Chaos and there's a second Civil War that would absolutely destroy the Imperium in a psychic war that could potentially create new Chaos gods. Just because people are suddenly ridiculously more powerful, psychically speaking, doesn't mean they're going to make good choices. Or as good as those choices could be from 40K.

Said Civil War 2: Psychic Boogaloo, will either result in the genocides of the Eldar (possibly) and the Tau (definitely). The Necrons will go "Fuck this," and either release the C'tan from their pokeballs or go into hibernation for another couple of hundred thousand years. Most likely they'll accelerate their waking up and attempt to eradicate all life in the galaxy. The Tyranids will be attracted by the giant psychic flare and the main body will arrive to eat what's left. The Orks will continue as they have been.

The Orks would be absolutely pulverized in such a situation.

How does humanity procreate now? Astartes are sterile.

Entirely varies depending on source.