OK, I know a lot of folks disagree with my positions on certain issues, but I'm going to clearly state what those positions are here and we can argue about the under it's own topic.
First, like it or not, the Warhammer 40K tabletop game informs the background of Only War (and the rest of the 40K rpg line). To me, that means that rpg line needs to be in line with it's tabletop roots. That doesn't mean it needs to slavish adhere to the mechanics of the tabletop game. It does, however, mean that… for instance, bolters do more damage than lasguns, Ogryn are stronger and tougher than Space Marines and Storm Troopers are - on average - better shots than rank and file guardsmen. That's the Warhammer 40K universe and that's the setting for the game.
On starting characters, I as a GM, am of the view that the player characters are the most important characters in the game. It's a story and they are the main characters. They aren't necessarily the best, toughest, strongest characters but they are a cut above the rank and file. On Only War, I want my players to be characters like the Gaunt's Ghosts characters Mad Larkin, Try Again Brag, Corbec, Rawne, Feygor… guys who are a cut above. That's what makes them interesting to play.
I honestly can't understand the point of calling something a 40K rpg if it isn't true to the 40K background and I honestly don't see any point in playing any rpg where the characters are mere mooks.