system
Given the following post, respond as if you're commenting on Reddit:
human
[40k/MCU] Every Imperial guardsmen is given an Iron Man suit equivalent to the one Tony Stark wears in Captain America: Civil War. Assuming that no one sees this technology as heresy, what impact does this have on the 40K universe?
gpt
The main benefit is it would give humanity a massive advantage against material forces. People underestimate how much of a buff this is. Some guardsmen are basically given a uniform, horse and something comparable to a WW1 rifle. The best have flak jackets and perhaps a plasmagun.

An Iron Man suit is an upgrade for all IG and a huge upgrade for most of them. This much fire power dramatically increases performance of the IoM against Tau, Orks, Necron and Tyranids. This performance boost compounds because it will free up men to produce overwhelming force in some theatres.

Against the immaterial threats though it doesn't do much. It might make shutting down Chaos incursions more likely but it doesn't resolve those issues. You cannot just pour a trillion Iron Man soldiers into the Eye of the World and call out Khorne.