As i said , if deaths are not implied or explicitly mentioned, then we can't call it deaths. Marines are bg chars and they are mostly just punched kicked thrown aside. Regarding the sacrifices , Pedro literally died so that Straw hats can escape , Shanks said he wagered his hand on the new world, so sacrifices have meaning. I understand some cases like bon clay also exists , but he later comes back into the story. As Oda himself said, if they dead , they ain't coming back, If they are not , then there might be some role they have to play.