i'm sure a ww1 shooter will sell well in AUS/NZ/CAN at least, but i think the horror of the somme or the waste of gallipolli would best be in a survival rpg. "can you make it home?" and have it worse than dark souls, because in death you don't really learn anything
the campaign would probably be cool anyway, and maybe some people might learn a modicum of history. i dunno about the multiplayer though, but the video seems faster paced than it actually was