Yeah, I dunno. They sound more British, but that's probably just because GW is a British company. THQ might be as well, dunno.
Anyway, this theoretical WH40k: Silent Storm would be better served by making the characters from a penal legion, so that you get a wide variety of voices and appearances.
Penal Legion game would be fucking boring because it would be CHAAAARGEEE and if you tried to do anything else than running up to enemy while shooting you would get exploded, so GAME OVER. That is why Inquisitorial Stormtroopers would be better. They can come from anywhere (not even be Imperial Guardsmen), have easier access to bigger variety of equipment, be actually trusted to not wear an explosive collar 24/7, get to actually do tactics and stuff...
So basically, we need
All Guardsmen Party: The Game.
EDIT:
Also, yeah, Cadia
is was a bit of like Canada, but other than some bits (TINY BITS),
they're mostly just Generic Occidental Army actually, no, they're fucking Grimdark Generic Occidental Army. AFAIK, Cadians only control 30% of Cadia, with Chaos forces controlling the remaining 30% (where's the 40% you ask? It's a no-mans land that isin't even land anymore, it's dead bodies now). Cadia may have been like Canada, but nowadays it's just a horrible hellhole where nobody cares about what it is anymore, a place where you learn how to shoot so young that when you're toilet-trained you're told to aim your dick like it's a lasgun. And the only reason they're not all dead is Creed tactical genius which makes Titans and Baneblades and stuff appear out of nowhere. In Cadia, wind doesn't blow. It sucks.