a human being using a fatman as a weapon, would be completely unable to carry any other item...whether or not he was using a backpack, satchel, rucksack, etc....
backpacks don't answer the question well enough. just having a knapsack on your player model does not justify carrying 4 to 10 guns around (not to mention ammunition)...nobody can do it...even real-world soldiers rarely carry more than a rifle and sidearm. and what kind of backpacks do you know of that can hold ammunition crates of ammo and 6-foot claymores?
adding backpacks doesn't 'fix' the realism to me...it just raises further questions. if you ask me, 'hammerspace' has always worked and will continue to work in future action titles...
