Just because the IG is squishier than other factions doesn't mean they're weak. In the 40K universe they do most of the heavy lifting as far as ground fighting goes for the Imperium, and they seem to do a decent job of it.
When the fate of the universe rests in the hands of 1 man. you dont want it to be a guardsmen. Thats all im saying.
you can count on the guardsmen to do 2 things. Hold the line, and **** themselves while doing it.