A bunch of gauze is always useful and light, or at least something you'd be willing to soak up large amounts of blood with. And an ace wrap or similar. Several pairs of nitrile gloves would be good, as once you get one set bloody, you can't do much else, and also you can give them to people to assist you. Steri-strips and Benzoine are a nice touch for minor lacerations (esp. on the face, when it will be a long time before you get out of the backcountry), but you need to practice with them. Don't carry too much, because in reality, there's just not much in a first aid kit that can help someone who is really hurt. You can improv. a lot if you are willing to get gear bloody.